Searched +hist:3 +hist:f8206d4 (Results 1 - 4 of 4) sorted by relevance
| /linux-master/fs/ubifs/ | ||
| H A D | file.c | diff 541d4c79 Mon Aug 07 13:38:34 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: drop the timespec64 arg from generic_update_time In future patches we're going to change how the ctime is updated to keep track of when it has been queried. The way that the update_time operation works (and a lot of its callers) make this difficult, since they grab a timestamp early and then pass it down to eventually be copied into the inode. All of the existing update_time callers pass in the result of current_time() in some fashion. Drop the "time" parameter from generic_update_time, and rework it to fetch its own timestamp. This change means that an update_time could fetch a different timestamp than was seen in inode_needs_update_time. update_time is only ever called with one of two flag combinations: Either S_ATIME is set, or S_MTIME|S_CTIME|S_VERSION are set. With this change we now treat the flags argument as an indicator that some value needed to be updated when last checked, rather than an indication to update specific timestamps. Rework the logic for updating the timestamps and put it in a new inode_update_timestamps helper that other update_time routines can use. S_ATIME is as treated as we always have, but if any of the other three are set, then we attempt to update all three. Also, some callers of generic_update_time need to know what timestamps were actually updated. Change it to return an S_* flag mask to indicate that and rework the callers to expect it. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230807-mgctime-v7-3-d1dec143a704@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> diff 3b67db8a Sun Dec 26 20:22:41 MST 2021 Zhihao Cheng <chengzhihao1@huawei.com> ubifs: Fix to add refcount once page is set private MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. Otherwise, we may get a BUG in page migration: page:0000000080d05b9d refcount:-1 mapcount:0 mapping:000000005f4d82a8 index:0xe2 pfn:0x14c12 aops:ubifs_file_address_operations [ubifs] ino:8f1 dentry name:"f30e" flags: 0x1fffff80002405(locked|uptodate|owner_priv_1|private|node=0| zone=1|lastcpupid=0x1fffff) page dumped because: VM_BUG_ON_PAGE(page_count(page) != 0) ------------[ cut here ]------------ kernel BUG at include/linux/page_ref.h:184! invalid opcode: 0000 [#1] SMP CPU: 3 PID: 38 Comm: kcompactd0 Not tainted 5.15.0-rc5 RIP: 0010:migrate_page_move_mapping+0xac3/0xe70 Call Trace: ubifs_migrate_page+0x22/0xc0 [ubifs] move_to_new_page+0xb4/0x600 migrate_pages+0x1523/0x1cc0 compact_zone+0x8c5/0x14b0 kcompactd+0x2bc/0x560 kthread+0x18c/0x1e0 ret_from_fork+0x1f/0x30 Before the time, we should make clean a concept, what does refcount means in page gotten from grab_cache_page_write_begin(). There are 2 situations: Situation 1: refcount is 3, page is created by __page_cache_alloc. TYPE_A - the write process is using this page TYPE_B - page is assigned to one certain mapping by calling __add_to_page_cache_locked() TYPE_C - page is added into pagevec list corresponding current cpu by calling lru_cache_add() Situation 2: refcount is 2, page is gotten from the mapping's tree TYPE_B - page has been assigned to one certain mapping TYPE_A - the write process is using this page (by calling page_cache_get_speculative()) Filesystem releases one refcount by calling put_page() in xxx_write_end(), the released refcount corresponds to TYPE_A (write task is using it). If there are any processes using a page, page migration process will skip the page by judging whether expected_page_refs() equals to page refcount. The BUG is caused by following process: PA(cpu 0) kcompactd(cpu 1) compact_zone ubifs_write_begin page_a = grab_cache_page_write_begin add_to_page_cache_lru lru_cache_add pagevec_add // put page into cpu 0's pagevec (refcnf = 3, for page creation process) ubifs_write_end SetPagePrivate(page_a) // doesn't increase page count ! unlock_page(page_a) put_page(page_a) // refcnt = 2 [...] PB(cpu 0) filemap_read filemap_get_pages add_to_page_cache_lru lru_cache_add __pagevec_lru_add // traverse all pages in cpu 0's pagevec __pagevec_lru_add_fn SetPageLRU(page_a) isolate_migratepages isolate_migratepages_block get_page_unless_zero(page_a) // refcnt = 3 list_add(page_a, from_list) migrate_pages(from_list) __unmap_and_move move_to_new_page ubifs_migrate_page(page_a) migrate_page_move_mapping expected_page_refs get 3 (migration[1] + mapping[1] + private[1]) release_pages put_page_testzero(page_a) // refcnt = 3 page_ref_freeze // refcnt = 0 page_ref_dec_and_test(0 - 1 = -1) page_ref_unfreeze VM_BUG_ON_PAGE(-1 != 0, page) UBIFS doesn't increase the page refcount after setting private flag, which leads to page migration task believes the page is not used by any other processes, so the page is migrated. This causes concurrent accessing on page refcount between put_page() called by other process(eg. read process calls lru_cache_add) and page_ref_unfreeze() called by migration task. Actually zhangjun has tried to fix this problem [2] by recalculating page refcnt in ubifs_migrate_page(). It's better to follow MM rules [1], because just like Kirill suggested in [2], we need to check all users of page_has_private() helper. Like f2fs does in [3], fix it by adding/deleting refcount when setting/clearing private for a page. BTW, according to [4], we set 'page->private' as 1 because ubifs just simply SetPagePrivate(). And, [5] provided a common helper to set/clear page private, ubifs can use this helper following the example of iomap, afs, btrfs, etc. Jump [6] to find a reproducer. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com [2] https://www.spinics.net/lists/linux-mtd/msg04018.html [3] http://lkml.iu.edu/hypermail/linux/kernel/1903.0/03313.html [4] https://lore.kernel.org/linux-f2fs-devel/20210422154705.GO3596236@casper.infradead.org [5] https://lore.kernel.org/all/20200517214718.468-1-guoqing.jiang@cloud.ionos.com [6] https://bugzilla.kernel.org/show_bug.cgi?id=214961 Fixes: 1e51764a3c2ac0 ("UBIFS: add new flash file system") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> |
| /linux-master/fs/nfsd/ | ||
| H A D | nfsctl.c | diff ed9ab734 Fri Jun 16 15:51:34 MDT 2023 Jeff Layton <jlayton@kernel.org> nfsd: move init of percpu reply_cache_stats counters back to nfsd_init_net Commit f5f9d4a314da ("nfsd: move reply cache initialization into nfsd startup") moved the initialization of the reply cache into nfsd startup, but didn't account for the stats counters, which can be accessed before nfsd is ever started. The result can be a NULL pointer dereference when someone accesses /proc/fs/nfsd/reply_cache_stats while nfsd is still shut down. This is a regression and a user-triggerable oops in the right situation: - non-x86_64 arch - /proc/fs/nfsd is mounted in the namespace - nfsd is not started in the namespace - unprivileged user calls "cat /proc/fs/nfsd/reply_cache_stats" Although this is easy to trigger on some arches (like aarch64), on x86_64, calling this_cpu_ptr(NULL) evidently returns a pointer to the fixed_percpu_data. That struct looks just enough like a newly initialized percpu var to allow nfsd_reply_cache_stats_show to access it without Oopsing. Move the initialization of the per-net+per-cpu reply-cache counters back into nfsd_init_net, while leaving the rest of the reply cache allocations to be done at nfsd startup time. Kudos to Eirik who did most of the legwork to track this down. Cc: stable@vger.kernel.org # v6.3+ Fixes: f5f9d4a314da ("nfsd: move reply cache initialization into nfsd startup") Reported-and-tested-by: Eirik Fuller <efuller@redhat.com> Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2215429 Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> diff 2f3a4b2a Tue Oct 18 05:47:56 MDT 2022 Jeff Layton <jlayton@kernel.org> nfsd: allow disabling NFSv2 at compile time rpc.nfsd stopped supporting NFSv2 a year ago. Take the next logical step toward deprecating it and allow NFSv2 support to be compiled out. Add a new CONFIG_NFSD_V2 option that can be turned off and rework the CONFIG_NFSD_V?_ACL option dependencies. Add a description that discourages enabling it. Also, change the description of CONFIG_NFSD to state that the always-on version is now 3 instead of 2. Finally, add an #ifdef around "case 2:" in __write_versions. When NFSv2 is disabled at compile time, this should make the kernel ignore attempts to disable it at runtime, but still error out when trying to enable it. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Tom Talpey <tom@talpey.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> diff 3a5940bf Wed Jul 20 06:39:23 MDT 2022 Jeff Layton <jlayton@kernel.org> nfsd: silence extraneous printk on nfsd.ko insertion This printk pops every time nfsd.ko gets plugged in. Most kmods don't do that and this one is not very informative. Olaf's email address seems to be defunct at this point anyway. Just drop it. Cc: Olaf Kirch <okir@suse.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> diff 29044dae Thu Jan 20 14:53:05 MST 2022 Amir Goldstein <amir73il@gmail.com> fsnotify: fix fsnotify hooks in pseudo filesystems Commit 49246466a989 ("fsnotify: move fsnotify_nameremove() hook out of d_delete()") moved the fsnotify delete hook before d_delete() so fsnotify will have access to a positive dentry. This allowed a race where opening the deleted file via cached dentry is now possible after receiving the IN_DELETE event. To fix the regression in pseudo filesystems, convert d_delete() calls to d_drop() (see commit 46c46f8df9aa ("devpts_pty_kill(): don't bother with d_delete()") and move the fsnotify hook after d_drop(). Add a missing fsnotify_unlink() hook in nfsdfs that was found during the audit of fsnotify hooks in pseudo filesystems. Note that the fsnotify hooks in simple_recursive_removal() follow d_invalidate(), so they require no change. Link: https://lore.kernel.org/r/20220120215305.282577-2-amir73il@gmail.com Reported-by: Ivan Delalande <colona@arista.com> Link: https://lore.kernel.org/linux-fsdevel/YeNyzoDM5hP5LtGW@visor/ Fixes: 49246466a989 ("fsnotify: move fsnotify_nameremove() hook out of d_delete()") Cc: stable@vger.kernel.org # v5.3+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> diff bd5ae928 Wed Feb 03 09:42:13 MST 2021 J. Bruce Fields <bfields@redhat.com> nfsd: register pernet ops last, unregister first These pernet operations may depend on stuff set up or torn down in the module init/exit functions. And they may be called at any time in between. So it makes more sense for them to be the last to be registered in the init function, and the first to be unregistered in the exit function. In particular, without this, the drc slab is being destroyed before all the per-net drcs are shut down, resulting in an "Objects remaining in nfsd_drc on __kmem_cache_shutdown()" warning in exit_nfsd. Reported-by: Zhi Li <yieli@redhat.com> Fixes: 3ba75830ce17 "nfsd4: drc containerization" Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> diff 3f649ab7 Wed Jun 03 14:09:38 MDT 2020 Kees Cook <keescook@chromium.org> treewide: Remove uninitialized_var() usage Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var\(([^\)]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs Signed-off-by: Kees Cook <keescook@chromium.org> diff 3f649ab7 Wed Jun 03 14:09:38 MDT 2020 Kees Cook <keescook@chromium.org> treewide: Remove uninitialized_var() usage Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var\(([^\)]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs Signed-off-by: Kees Cook <keescook@chromium.org> diff 3f649ab7 Wed Jun 03 14:09:38 MDT 2020 Kees Cook <keescook@chromium.org> treewide: Remove uninitialized_var() usage Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var\(([^\)]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs Signed-off-by: Kees Cook <keescook@chromium.org> diff 027690c7 Mon Jun 01 15:44:45 MDT 2020 J. Bruce Fields <bfields@redhat.com> nfsd4: make drc_slab global, not per-net I made every global per-network-namespace instead. But perhaps doing that to this slab was a step too far. The kmem_cache_create call in our net init method also seems to be responsible for this lockdep warning: [ 45.163710] Unable to find swap-space signature [ 45.375718] trinity-c1 (855): attempted to duplicate a private mapping with mremap. This is not supported. [ 46.055744] futex_wake_op: trinity-c1 tries to shift op by -209; fix this program [ 51.011723] [ 51.013378] ====================================================== [ 51.013875] WARNING: possible circular locking dependency detected [ 51.014378] 5.2.0-rc2 #1 Not tainted [ 51.014672] ------------------------------------------------------ [ 51.015182] trinity-c2/886 is trying to acquire lock: [ 51.015593] 000000005405f099 (slab_mutex){+.+.}, at: slab_attr_store+0xa2/0x130 [ 51.016190] [ 51.016190] but task is already holding lock: [ 51.016652] 00000000ac662005 (kn->count#43){++++}, at: kernfs_fop_write+0x286/0x500 [ 51.017266] [ 51.017266] which lock already depends on the new lock. [ 51.017266] [ 51.017909] [ 51.017909] the existing dependency chain (in reverse order) is: [ 51.018497] [ 51.018497] -> #1 (kn->count#43){++++}: [ 51.018956] __lock_acquire+0x7cf/0x1a20 [ 51.019317] lock_acquire+0x17d/0x390 [ 51.019658] __kernfs_remove+0x892/0xae0 [ 51.020020] kernfs_remove_by_name_ns+0x78/0x110 [ 51.020435] sysfs_remove_link+0x55/0xb0 [ 51.020832] sysfs_slab_add+0xc1/0x3e0 [ 51.021332] __kmem_cache_create+0x155/0x200 [ 51.021720] create_cache+0xf5/0x320 [ 51.022054] kmem_cache_create_usercopy+0x179/0x320 [ 51.022486] kmem_cache_create+0x1a/0x30 [ 51.022867] nfsd_reply_cache_init+0x278/0x560 [ 51.023266] nfsd_init_net+0x20f/0x5e0 [ 51.023623] ops_init+0xcb/0x4b0 [ 51.023928] setup_net+0x2fe/0x670 [ 51.024315] copy_net_ns+0x30a/0x3f0 [ 51.024653] create_new_namespaces+0x3c5/0x820 [ 51.025257] unshare_nsproxy_namespaces+0xd1/0x240 [ 51.025881] ksys_unshare+0x506/0x9c0 [ 51.026381] __x64_sys_unshare+0x3a/0x50 [ 51.026937] do_syscall_64+0x110/0x10b0 [ 51.027509] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.028175] [ 51.028175] -> #0 (slab_mutex){+.+.}: [ 51.028817] validate_chain+0x1c51/0x2cc0 [ 51.029422] __lock_acquire+0x7cf/0x1a20 [ 51.029947] lock_acquire+0x17d/0x390 [ 51.030438] __mutex_lock+0x100/0xfa0 [ 51.030995] mutex_lock_nested+0x27/0x30 [ 51.031516] slab_attr_store+0xa2/0x130 [ 51.032020] sysfs_kf_write+0x11d/0x180 [ 51.032529] kernfs_fop_write+0x32a/0x500 [ 51.033056] do_loop_readv_writev+0x21d/0x310 [ 51.033627] do_iter_write+0x2e5/0x380 [ 51.034148] vfs_writev+0x170/0x310 [ 51.034616] do_pwritev+0x13e/0x160 [ 51.035100] __x64_sys_pwritev+0xa3/0x110 [ 51.035633] do_syscall_64+0x110/0x10b0 [ 51.036200] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.036924] [ 51.036924] other info that might help us debug this: [ 51.036924] [ 51.037876] Possible unsafe locking scenario: [ 51.037876] [ 51.038556] CPU0 CPU1 [ 51.039130] ---- ---- [ 51.039676] lock(kn->count#43); [ 51.040084] lock(slab_mutex); [ 51.040597] lock(kn->count#43); [ 51.041062] lock(slab_mutex); [ 51.041320] [ 51.041320] *** DEADLOCK *** [ 51.041320] [ 51.041793] 3 locks held by trinity-c2/886: [ 51.042128] #0: 000000001f55e152 (sb_writers#5){.+.+}, at: vfs_writev+0x2b9/0x310 [ 51.042739] #1: 00000000c7d6c034 (&of->mutex){+.+.}, at: kernfs_fop_write+0x25b/0x500 [ 51.043400] #2: 00000000ac662005 (kn->count#43){++++}, at: kernfs_fop_write+0x286/0x500 Reported-by: kernel test robot <lkp@intel.com> Fixes: 3ba75830ce17 "drc containerization" Signed-off-by: J. Bruce Fields <bfields@redhat.com> diff 027690c7 Mon Jun 01 15:44:45 MDT 2020 J. Bruce Fields <bfields@redhat.com> nfsd4: make drc_slab global, not per-net I made every global per-network-namespace instead. But perhaps doing that to this slab was a step too far. The kmem_cache_create call in our net init method also seems to be responsible for this lockdep warning: [ 45.163710] Unable to find swap-space signature [ 45.375718] trinity-c1 (855): attempted to duplicate a private mapping with mremap. This is not supported. [ 46.055744] futex_wake_op: trinity-c1 tries to shift op by -209; fix this program [ 51.011723] [ 51.013378] ====================================================== [ 51.013875] WARNING: possible circular locking dependency detected [ 51.014378] 5.2.0-rc2 #1 Not tainted [ 51.014672] ------------------------------------------------------ [ 51.015182] trinity-c2/886 is trying to acquire lock: [ 51.015593] 000000005405f099 (slab_mutex){+.+.}, at: slab_attr_store+0xa2/0x130 [ 51.016190] [ 51.016190] but task is already holding lock: [ 51.016652] 00000000ac662005 (kn->count#43){++++}, at: kernfs_fop_write+0x286/0x500 [ 51.017266] [ 51.017266] which lock already depends on the new lock. [ 51.017266] [ 51.017909] [ 51.017909] the existing dependency chain (in reverse order) is: [ 51.018497] [ 51.018497] -> #1 (kn->count#43){++++}: [ 51.018956] __lock_acquire+0x7cf/0x1a20 [ 51.019317] lock_acquire+0x17d/0x390 [ 51.019658] __kernfs_remove+0x892/0xae0 [ 51.020020] kernfs_remove_by_name_ns+0x78/0x110 [ 51.020435] sysfs_remove_link+0x55/0xb0 [ 51.020832] sysfs_slab_add+0xc1/0x3e0 [ 51.021332] __kmem_cache_create+0x155/0x200 [ 51.021720] create_cache+0xf5/0x320 [ 51.022054] kmem_cache_create_usercopy+0x179/0x320 [ 51.022486] kmem_cache_create+0x1a/0x30 [ 51.022867] nfsd_reply_cache_init+0x278/0x560 [ 51.023266] nfsd_init_net+0x20f/0x5e0 [ 51.023623] ops_init+0xcb/0x4b0 [ 51.023928] setup_net+0x2fe/0x670 [ 51.024315] copy_net_ns+0x30a/0x3f0 [ 51.024653] create_new_namespaces+0x3c5/0x820 [ 51.025257] unshare_nsproxy_namespaces+0xd1/0x240 [ 51.025881] ksys_unshare+0x506/0x9c0 [ 51.026381] __x64_sys_unshare+0x3a/0x50 [ 51.026937] do_syscall_64+0x110/0x10b0 [ 51.027509] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.028175] [ 51.028175] -> #0 (slab_mutex){+.+.}: [ 51.028817] validate_chain+0x1c51/0x2cc0 [ 51.029422] __lock_acquire+0x7cf/0x1a20 [ 51.029947] lock_acquire+0x17d/0x390 [ 51.030438] __mutex_lock+0x100/0xfa0 [ 51.030995] mutex_lock_nested+0x27/0x30 [ 51.031516] slab_attr_store+0xa2/0x130 [ 51.032020] sysfs_kf_write+0x11d/0x180 [ 51.032529] kernfs_fop_write+0x32a/0x500 [ 51.033056] do_loop_readv_writev+0x21d/0x310 [ 51.033627] do_iter_write+0x2e5/0x380 [ 51.034148] vfs_writev+0x170/0x310 [ 51.034616] do_pwritev+0x13e/0x160 [ 51.035100] __x64_sys_pwritev+0xa3/0x110 [ 51.035633] do_syscall_64+0x110/0x10b0 [ 51.036200] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 51.036924] [ 51.036924] other info that might help us debug this: [ 51.036924] [ 51.037876] Possible unsafe locking scenario: [ 51.037876] [ 51.038556] CPU0 CPU1 [ 51.039130] ---- ---- [ 51.039676] lock(kn->count#43); [ 51.040084] lock(slab_mutex); [ 51.040597] lock(kn->count#43); [ 51.041062] lock(slab_mutex); [ 51.041320] [ 51.041320] *** DEADLOCK *** [ 51.041320] [ 51.041793] 3 locks held by trinity-c2/886: [ 51.042128] #0: 000000001f55e152 (sb_writers#5){.+.+}, at: vfs_writev+0x2b9/0x310 [ 51.042739] #1: 00000000c7d6c034 (&of->mutex){+.+.}, at: kernfs_fop_write+0x25b/0x500 [ 51.043400] #2: 00000000ac662005 (kn->count#43){++++}, at: kernfs_fop_write+0x286/0x500 Reported-by: kernel test robot <lkp@intel.com> Fixes: 3ba75830ce17 "drc containerization" Signed-off-by: J. Bruce Fields <bfields@redhat.com> |
| /linux-master/include/linux/ | ||
| H A D | nfs_fs.h | diff 3db63daa Tue Mar 21 16:27:04 MDT 2023 NeilBrown <neilb@suse.de> NFSv3: handle out-of-order write replies. NFSv3 includes pre/post wcc attributes which allow the client to determine if all changes to the file have been made by the client itself, or if any might have been made by some other client. If there are gaps in the pre/post ctime sequence it must be assumed that some other client changed the file in that gap and the local cache must be suspect. The next time the file is opened the cache should be invalidated. Since Commit 1c341b777501 ("NFS: Add deferred cache invalidation for close-to-open consistency violations") in linux 5.3 the Linux client has been triggering this invalidation. The chunk in nfs_update_inode() in particularly triggers. Unfortunately Linux NFS assumes that all replies will be processed in the order sent, and will arrive in the order processed. This is not true in general. Consequently Linux NFS might ignore the wcc info in a WRITE reply because the reply is in response to a WRITE that was sent before some other request for which a reply has already been seen. This is detected by Linux using the gencount tests in nfs_inode_attr_cmp(). Also, when the gencount tests pass it is still possible that the request were processed on the server in a different order, and a gap seen in the ctime sequence might be filled in by a subsequent reply, so gaps should not immediately trigger delayed invalidation. The net result is that writing to a server and then reading the file back can result in going to the server for the read rather than serving it from cache - all because a couple of replies arrived out-of-order. This is a performance regression over kernels before 5.3, though the change in 5.3 is a correctness improvement. This has been seen with Linux writing to a Netapp server which occasionally re-orders requests. In testing the majority of requests were in-order, but a few (maybe 2 or three at a time) could be re-ordered. This patch addresses the problem by recording any gaps seen in the pre/post ctime sequence and not triggering invalidation until either there are too many gaps to fit in the table, or until there are no more active writes and the remaining gaps cannot be resolved. We allocate a table of 16 gaps on demand. If the allocation fails we revert to current behaviour which is of little cost as we are unlikely to be able to cache the writes anyway. In the table we store "start->end" pair when iversion is updated and "end<-start" pairs pre/post pairs reported by the server. Usually these exactly cancel out and so nothing is stored. When there are out-of-order replies we do store gaps and these will eventually be cancelled against later replies when this client is the only writer. If the final write is out-of-order there may be one gap remaining when the file is closed. This will be noticed and if there is precisely on gap and if the iversion can be advanced to match it, then we do so. This patch makes no attempt to handle directories correctly. The same problem potentially exists in the out-of-order replies to create/unlink requests can cause future lookup requires to be sent to the server unnecessarily. A similar scheme using the same primitives could be used to notice and handle out-of-order replies. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> diff 3c59366c Sun Jul 31 18:33:34 MDT 2022 NeilBrown <neilb@suse.de> NFS: don't unhash dentry during unlink/rename NFS unlink() (and rename over existing target) must determine if the file is open, and must perform a "silly rename" instead of an unlink (or before rename) if it is. Otherwise the client might hold a file open which has been removed on the server. Consequently if it determines that the file isn't open, it must block any subsequent opens until the unlink/rename has been completed on the server. This is currently achieved by unhashing the dentry. This forces any open attempt to the slow-path for lookup which will block on i_rwsem on the directory until the unlink/rename completes. A future patch will change the VFS to only get a shared lock on i_rwsem for unlink, so this will no longer work. Instead we introduce an explicit interlock. A special value is stored in dentry->d_fsdata while the unlink/rename is running and ->d_revalidate blocks while that value is present. When ->d_revalidate unblocks, the dentry will be invalid. This closes the race without requiring exclusion on i_rwsem. d_fsdata is already used in two different ways. 1/ an IS_ROOT directory dentry might have a "devname" stored in d_fsdata. Such a dentry doesn't have a name and so cannot be the target of unlink or rename. For safety we check if an old devname is still stored, and remove it if it is. 2/ a dentry with DCACHE_NFSFS_RENAMED set will have a 'struct nfs_unlinkdata' stored in d_fsdata. While this is set maydelete() will fail, so an unlink or rename will never proceed on such a dentry. Neither of these can be in effect when a dentry is the target of unlink or rename. So we can expect d_fsdata to be NULL, and store a special value ((void*)1) which is given the name NFS_FSDATA_BLOCKED to indicate that any lookup will be blocked. The d_count() is incremented under d_lock() when a lookup finds the dentry, so we check d_count() is low, and set NFS_FSDATA_BLOCKED under the same lock to avoid any races. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> diff a6b5a28e Sat Nov 14 11:43:54 MST 2020 Dave Wysochanski <dwysocha@redhat.com> nfs: Convert to new fscache volume/cookie API Change the nfs filesystem to support fscache's indexing rewrite and reenable caching in nfs. The following changes have been made: (1) The fscache_netfs struct is no more, and there's no need to register the filesystem as a whole. (2) The session cookie is now an fscache_volume cookie, allocated with fscache_acquire_volume(). That takes three parameters: a string representing the "volume" in the index, a string naming the cache to use (or NULL) and a u64 that conveys coherency metadata for the volume. For nfs, I've made it render the volume name string as: "nfs,<ver>,<family>,<address>,<port>,<fsidH>,<fsidL>*<,param>[,<uniq>]" (3) The fscache_cookie_def is no more and needed information is passed directly to fscache_acquire_cookie(). The cache no longer calls back into the filesystem, but rather metadata changes are indicated at other times. fscache_acquire_cookie() is passed the same keying and coherency information as before. (4) fscache_enable/disable_cookie() have been removed. Call fscache_use_cookie() and fscache_unuse_cookie() when a file is opened or closed to prevent a cache file from being culled and to keep resources to hand that are needed to do I/O. If a file is opened for writing, we invalidate it with FSCACHE_INVAL_DIO_WRITE in lieu of doing writeback to the cache, thereby making it cease caching until all currently open files are closed. This should give the same behaviour as the uptream code. Making the cache store local modifications isn't straightforward for NFS, so that's left for future patches. (5) fscache_invalidate() now needs to be given uptodate auxiliary data and a file size. It also takes a flag to indicate if this was due to a DIO write. (6) Call nfs_fscache_invalidate() with FSCACHE_INVAL_DIO_WRITE on a file to which a DIO write is made. (7) Call fscache_note_page_release() from nfs_release_page(). (8) Use a killable wait in nfs_vm_page_mkwrite() when waiting for PG_fscache to be cleared. (9) The functions to read and write data to/from the cache are stubbed out pending a conversion to use netfslib. Changes ======= ver #3: - Added missing =n fallback for nfs_fscache_release_file()[1][2]. ver #2: - Use gfpflags_allow_blocking() rather than using flag directly. - fscache_acquire_volume() now returns errors. - Remove NFS_INO_FSCACHE as it's no longer used. - Need to unuse a cookie on file-release, not inode-clear. Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Co-developed-by: David Howells <dhowells@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org> cc: Trond Myklebust <trond.myklebust@hammerspace.com> cc: Anna Schumaker <anna.schumaker@netapp.com> cc: linux-nfs@vger.kernel.org cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/202112100804.nksO8K4u-lkp@intel.com/ [1] Link: https://lore.kernel.org/r/202112100957.2oEDT20W-lkp@intel.com/ [2] Link: https://lore.kernel.org/r/163819668938.215744.14448852181937731615.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906979003.143852.2601189243864854724.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967182112.1823006.7791504655391213379.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021575950.640689.12069642327533368467.stgit@warthog.procyon.org.uk/ # v4 diff a6b5a28e Sat Nov 14 11:43:54 MST 2020 Dave Wysochanski <dwysocha@redhat.com> nfs: Convert to new fscache volume/cookie API Change the nfs filesystem to support fscache's indexing rewrite and reenable caching in nfs. The following changes have been made: (1) The fscache_netfs struct is no more, and there's no need to register the filesystem as a whole. (2) The session cookie is now an fscache_volume cookie, allocated with fscache_acquire_volume(). That takes three parameters: a string representing the "volume" in the index, a string naming the cache to use (or NULL) and a u64 that conveys coherency metadata for the volume. For nfs, I've made it render the volume name string as: "nfs,<ver>,<family>,<address>,<port>,<fsidH>,<fsidL>*<,param>[,<uniq>]" (3) The fscache_cookie_def is no more and needed information is passed directly to fscache_acquire_cookie(). The cache no longer calls back into the filesystem, but rather metadata changes are indicated at other times. fscache_acquire_cookie() is passed the same keying and coherency information as before. (4) fscache_enable/disable_cookie() have been removed. Call fscache_use_cookie() and fscache_unuse_cookie() when a file is opened or closed to prevent a cache file from being culled and to keep resources to hand that are needed to do I/O. If a file is opened for writing, we invalidate it with FSCACHE_INVAL_DIO_WRITE in lieu of doing writeback to the cache, thereby making it cease caching until all currently open files are closed. This should give the same behaviour as the uptream code. Making the cache store local modifications isn't straightforward for NFS, so that's left for future patches. (5) fscache_invalidate() now needs to be given uptodate auxiliary data and a file size. It also takes a flag to indicate if this was due to a DIO write. (6) Call nfs_fscache_invalidate() with FSCACHE_INVAL_DIO_WRITE on a file to which a DIO write is made. (7) Call fscache_note_page_release() from nfs_release_page(). (8) Use a killable wait in nfs_vm_page_mkwrite() when waiting for PG_fscache to be cleared. (9) The functions to read and write data to/from the cache are stubbed out pending a conversion to use netfslib. Changes ======= ver #3: - Added missing =n fallback for nfs_fscache_release_file()[1][2]. ver #2: - Use gfpflags_allow_blocking() rather than using flag directly. - fscache_acquire_volume() now returns errors. - Remove NFS_INO_FSCACHE as it's no longer used. - Need to unuse a cookie on file-release, not inode-clear. Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Co-developed-by: David Howells <dhowells@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org> cc: Trond Myklebust <trond.myklebust@hammerspace.com> cc: Anna Schumaker <anna.schumaker@netapp.com> cc: linux-nfs@vger.kernel.org cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/202112100804.nksO8K4u-lkp@intel.com/ [1] Link: https://lore.kernel.org/r/202112100957.2oEDT20W-lkp@intel.com/ [2] Link: https://lore.kernel.org/r/163819668938.215744.14448852181937731615.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906979003.143852.2601189243864854724.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967182112.1823006.7791504655391213379.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021575950.640689.12069642327533368467.stgit@warthog.procyon.org.uk/ # v4 diff 3a39e778 Thu May 21 03:17:21 MDT 2020 Zheng Bin <zhengbin13@huawei.com> nfs: set invalid blocks after NFSv4 writes Use the following command to test nfsv4(size of file1M is 1MB): mount -t nfs -o vers=4.0,actimeo=60 127.0.0.1/dir1 /mnt cp file1M /mnt du -h /mnt/file1M -->0 within 60s, then 1M When write is done(cp file1M /mnt), will call this: nfs_writeback_done nfs4_write_done nfs4_write_done_cb nfs_writeback_update_inode nfs_post_op_update_inode_force_wcc_locked(change, ctime, mtime nfs_post_op_update_inode_force_wcc_locked nfs_set_cache_invalid nfs_refresh_inode_locked nfs_update_inode nfsd write response contains change, ctime, mtime, the flag will be clear after nfs_update_inode. Howerver, write response does not contain space_used, previous open response contains space_used whose value is 0, so inode->i_blocks is still 0. nfs_getattr -->called by "du -h" do_update |= force_sync || nfs_attribute_cache_expired -->false in 60s cache_validity = READ_ONCE(NFS_I(inode)->cache_validity) do_update |= cache_validity & (NFS_INO_INVALID_ATTR -->false if (do_update) { __nfs_revalidate_inode } Within 60s, does not send getattr request to nfsd, thus "du -h /mnt/file1M" is 0. Add a NFS_INO_INVALID_BLOCKS flag, set it when nfsv4 write is done. Fixes: 16e143751727 ("NFS: More fine grained attribute tracking") Signed-off-by: Zheng Bin <zhengbin13@huawei.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| H A D | fs.h | diff d3b1a9a7 Fri Feb 02 01:33:04 MST 2024 JonasZhou <JonasZhou@zhaoxin.com> fs/address_space: move i_mmap_rwsem to mitigate a false sharing with i_mmap. In the struct address_space, there is a 32-byte gap between i_mmap and i_mmap_rwsem. Due to the alignment of struct address_space variables to 8 bytes, in certain situations, i_mmap and i_mmap_rwsem may end up in the same CACHE line. While running Unixbench/execl, we observe high false sharing issues when accessing i_mmap against i_mmap_rwsem. We move i_mmap_rwsem after i_private_list, ensuring a 64-byte gap between i_mmap and i_mmap_rwsem. For Intel Silver machines (2 sockets) using kernel v6.8 rc-2, the score of Unixbench/execl improves by ~3.94%, and the score of Unixbench/shell improves by ~3.26%. Baseline: ------------------------------------------------------------- 162 546 748 11374 21 0xffff92e266af90c0 ------------------------------------------------------------- 46.89% 44.65% 0.00% 0.00% 0x0 1 1 0xffffffff86d5fb96 460 258 271 1069 32 [k] __handle_mm_fault [kernel.vmlinux] memory.c:2940 0 1 4.21% 4.41% 0.00% 0.00% 0x4 1 1 0xffffffff86d0ed54 473 311 288 95 28 [k] filemap_read [kernel.vmlinux] atomic.h:23 0 1 0.00% 0.00% 0.04% 4.76% 0x8 1 1 0xffffffff86d4bcf1 0 0 0 5 4 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:204 0 1 6.41% 6.02% 0.00% 0.00% 0x8 1 1 0xffffffff86d4ba85 411 271 339 210 32 [k] vma_interval_tree_insert [kernel.vmlinux] interval_tree.c:23 0 1 0.00% 0.00% 0.47% 95.24% 0x10 1 1 0xffffffff86d4bd34 0 0 0 74 32 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:339 0 1 0.37% 0.13% 0.00% 0.00% 0x10 1 1 0xffffffff86d4bb4f 328 212 380 7 5 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:338 0 1 5.13% 5.08% 0.00% 0.00% 0x10 1 1 0xffffffff86d4bb4b 416 255 357 197 32 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:338 0 1 1.10% 0.53% 0.00% 0.00% 0x28 1 1 0xffffffff86e06eb8 395 228 351 24 14 [k] do_dentry_open [kernel.vmlinux] open.c:966 0 1 1.10% 2.14% 57.07% 0.00% 0x38 1 1 0xffffffff878c9225 1364 792 462 7003 32 [k] down_write [kernel.vmlinux] atomic64_64.h:109 0 1 0.00% 0.00% 0.01% 0.00% 0x38 1 1 0xffffffff878c8e75 0 0 252 3 2 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:109 0 1 0.00% 0.13% 0.00% 0.00% 0x38 1 1 0xffffffff878c8e23 0 596 63 2 2 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:15 0 1 2.38% 2.94% 6.53% 0.00% 0x38 1 1 0xffffffff878c8ccb 1150 818 570 1197 32 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:109 0 1 30.59% 32.22% 0.00% 0.00% 0x38 1 1 0xffffffff878c8cb4 423 251 380 648 32 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:15 0 1 1.83% 1.74% 35.88% 0.00% 0x38 1 1 0xffffffff86b4f833 1217 1112 565 4586 32 [k] up_write [kernel.vmlinux] atomic64_64.h:91 0 1 with this change: ------------------------------------------------------------- 360 12 300 57 35 0xffff982cdae76400 ------------------------------------------------------------- 50.00% 59.67% 0.00% 0.00% 0x0 1 1 0xffffffff8215fb86 352 200 191 558 32 [k] __handle_mm_fault [kernel.vmlinux] memory.c:2940 0 1 8.33% 5.00% 0.00% 0.00% 0x4 1 1 0xffffffff8210ed44 370 284 263 42 24 [k] filemap_read [kernel.vmlinux] atomic.h:23 0 1 0.00% 0.00% 5.26% 2.86% 0x8 1 1 0xffffffff8214bce1 0 0 0 4 4 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:204 0 1 33.33% 14.33% 0.00% 0.00% 0x8 1 1 0xffffffff8214ba75 344 186 219 140 32 [k] vma_interval_tree_insert [kernel.vmlinux] interval_tree.c:23 0 1 0.00% 0.00% 94.74% 97.14% 0x10 1 1 0xffffffff8214bd24 0 0 0 88 29 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:339 0 1 8.33% 20.00% 0.00% 0.00% 0x10 1 1 0xffffffff8214bb3b 296 209 226 167 31 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:338 0 1 0.00% 0.67% 0.00% 0.00% 0x28 1 1 0xffffffff82206f45 0 140 334 4 3 [k] do_dentry_open [kernel.vmlinux] open.c:966 0 1 0.00% 0.33% 0.00% 0.00% 0x38 1 1 0xffffffff8250a6c4 0 286 126 5 5 [k] errseq_sample [kernel.vmlinux] errseq.c:125 0 Signed-off-by: JonasZhou <JonasZhou@zhaoxin.com> Link: https://lore.kernel.org/r/20240202083304.10995-1-JonasZhou-oc@zhaoxin.com Signed-off-by: Christian Brauner <brauner@kernel.org> diff d3b1a9a7 Fri Feb 02 01:33:04 MST 2024 JonasZhou <JonasZhou@zhaoxin.com> fs/address_space: move i_mmap_rwsem to mitigate a false sharing with i_mmap. In the struct address_space, there is a 32-byte gap between i_mmap and i_mmap_rwsem. Due to the alignment of struct address_space variables to 8 bytes, in certain situations, i_mmap and i_mmap_rwsem may end up in the same CACHE line. While running Unixbench/execl, we observe high false sharing issues when accessing i_mmap against i_mmap_rwsem. We move i_mmap_rwsem after i_private_list, ensuring a 64-byte gap between i_mmap and i_mmap_rwsem. For Intel Silver machines (2 sockets) using kernel v6.8 rc-2, the score of Unixbench/execl improves by ~3.94%, and the score of Unixbench/shell improves by ~3.26%. Baseline: ------------------------------------------------------------- 162 546 748 11374 21 0xffff92e266af90c0 ------------------------------------------------------------- 46.89% 44.65% 0.00% 0.00% 0x0 1 1 0xffffffff86d5fb96 460 258 271 1069 32 [k] __handle_mm_fault [kernel.vmlinux] memory.c:2940 0 1 4.21% 4.41% 0.00% 0.00% 0x4 1 1 0xffffffff86d0ed54 473 311 288 95 28 [k] filemap_read [kernel.vmlinux] atomic.h:23 0 1 0.00% 0.00% 0.04% 4.76% 0x8 1 1 0xffffffff86d4bcf1 0 0 0 5 4 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:204 0 1 6.41% 6.02% 0.00% 0.00% 0x8 1 1 0xffffffff86d4ba85 411 271 339 210 32 [k] vma_interval_tree_insert [kernel.vmlinux] interval_tree.c:23 0 1 0.00% 0.00% 0.47% 95.24% 0x10 1 1 0xffffffff86d4bd34 0 0 0 74 32 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:339 0 1 0.37% 0.13% 0.00% 0.00% 0x10 1 1 0xffffffff86d4bb4f 328 212 380 7 5 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:338 0 1 5.13% 5.08% 0.00% 0.00% 0x10 1 1 0xffffffff86d4bb4b 416 255 357 197 32 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:338 0 1 1.10% 0.53% 0.00% 0.00% 0x28 1 1 0xffffffff86e06eb8 395 228 351 24 14 [k] do_dentry_open [kernel.vmlinux] open.c:966 0 1 1.10% 2.14% 57.07% 0.00% 0x38 1 1 0xffffffff878c9225 1364 792 462 7003 32 [k] down_write [kernel.vmlinux] atomic64_64.h:109 0 1 0.00% 0.00% 0.01% 0.00% 0x38 1 1 0xffffffff878c8e75 0 0 252 3 2 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:109 0 1 0.00% 0.13% 0.00% 0.00% 0x38 1 1 0xffffffff878c8e23 0 596 63 2 2 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:15 0 1 2.38% 2.94% 6.53% 0.00% 0x38 1 1 0xffffffff878c8ccb 1150 818 570 1197 32 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:109 0 1 30.59% 32.22% 0.00% 0.00% 0x38 1 1 0xffffffff878c8cb4 423 251 380 648 32 [k] rwsem_down_write_slowpath [kernel.vmlinux] atomic64_64.h:15 0 1 1.83% 1.74% 35.88% 0.00% 0x38 1 1 0xffffffff86b4f833 1217 1112 565 4586 32 [k] up_write [kernel.vmlinux] atomic64_64.h:91 0 1 with this change: ------------------------------------------------------------- 360 12 300 57 35 0xffff982cdae76400 ------------------------------------------------------------- 50.00% 59.67% 0.00% 0.00% 0x0 1 1 0xffffffff8215fb86 352 200 191 558 32 [k] __handle_mm_fault [kernel.vmlinux] memory.c:2940 0 1 8.33% 5.00% 0.00% 0.00% 0x4 1 1 0xffffffff8210ed44 370 284 263 42 24 [k] filemap_read [kernel.vmlinux] atomic.h:23 0 1 0.00% 0.00% 5.26% 2.86% 0x8 1 1 0xffffffff8214bce1 0 0 0 4 4 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:204 0 1 33.33% 14.33% 0.00% 0.00% 0x8 1 1 0xffffffff8214ba75 344 186 219 140 32 [k] vma_interval_tree_insert [kernel.vmlinux] interval_tree.c:23 0 1 0.00% 0.00% 94.74% 97.14% 0x10 1 1 0xffffffff8214bd24 0 0 0 88 29 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:339 0 1 8.33% 20.00% 0.00% 0.00% 0x10 1 1 0xffffffff8214bb3b 296 209 226 167 31 [k] vma_interval_tree_remove [kernel.vmlinux] rbtree_augmented.h:338 0 1 0.00% 0.67% 0.00% 0.00% 0x28 1 1 0xffffffff82206f45 0 140 334 4 3 [k] do_dentry_open [kernel.vmlinux] open.c:966 0 1 0.00% 0.33% 0.00% 0.00% 0x38 1 1 0xffffffff8250a6c4 0 286 126 5 5 [k] errseq_sample [kernel.vmlinux] errseq.c:125 0 Signed-off-by: JonasZhou <JonasZhou@zhaoxin.com> Link: https://lore.kernel.org/r/20240202083304.10995-1-JonasZhou-oc@zhaoxin.com Signed-off-by: Christian Brauner <brauner@kernel.org> diff b820de74 Thu Feb 15 01:47:38 MST 2024 Bart Van Assche <bvanassche@acm.org> fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio If kiocb_set_cancel_fn() is called for I/O submitted via io_uring, the following kernel warning appears: WARNING: CPU: 3 PID: 368 at fs/aio.c:598 kiocb_set_cancel_fn+0x9c/0xa8 Call trace: kiocb_set_cancel_fn+0x9c/0xa8 ffs_epfile_read_iter+0x144/0x1d0 io_read+0x19c/0x498 io_issue_sqe+0x118/0x27c io_submit_sqes+0x25c/0x5fc __arm64_sys_io_uring_enter+0x104/0xab0 invoke_syscall+0x58/0x11c el0_svc_common+0xb4/0xf4 do_el0_svc+0x2c/0xb0 el0_svc+0x2c/0xa4 el0t_64_sync_handler+0x68/0xb4 el0t_64_sync+0x1a4/0x1a8 Fix this by setting the IOCB_AIO_RW flag for read and write I/O that is submitted by libaio. Suggested-by: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Cc: Avi Kivity <avi@scylladb.com> Cc: Sandeep Dhavale <dhavale@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: stable@vger.kernel.org Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20240215204739.2677806-2-bvanassche@acm.org Signed-off-by: Christian Brauner <brauner@kernel.org> diff 3efdc78f Wed Dec 13 23:44:38 MST 2023 Andrei Vagin <avagin@google.com> fs/proc: show correct device and inode numbers in /proc/pid/maps /proc/pid/maps shows device and inode numbers of vma->vm_file-s. Here is an issue. If a mapped file is on a stackable file system (e.g., overlayfs), vma->vm_file is a backing file whose f_inode is on the underlying filesystem. To show correct numbers, we need to get a user file and shows its numbers. The same trick is used to show file paths in /proc/pid/maps. Cc: Alexander Mikhalitsyn <alexander@mihalicyn.com> Suggested-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Andrei Vagin <avagin@google.com> Link: https://lore.kernel.org/r/20231214064439.1023011-1-avagin@google.com Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org> diff 705bcfcb Tue Dec 12 02:44:37 MST 2023 Amir Goldstein <amir73il@gmail.com> fs: use splice_copy_file_range() inline helper generic_copy_file_range() is just a wrapper around splice_file_range(), which caps the maximum copy length. The only caller of splice_file_range(), namely __ceph_copy_file_range() is already ready to cope with short copy. Move the length capping into splice_file_range() and replace the exported symbol generic_copy_file_range() with a simple inline helper. Suggested-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/linux-fsdevel/20231204083849.GC32438@lst.de/ Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231212094440.250945-3-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org> diff 372a34e6 Thu Nov 30 05:49:09 MST 2023 Christian Brauner <brauner@kernel.org> fs: replace f_rcuhead with f_task_work The naming is actively misleading since we switched to SLAB_TYPESAFE_BY_RCU. rcu_head is #define callback_head. Use callback_head directly and rename f_rcuhead to f_task_work. Add comments in there to explain what it's used for. Link: https://lore.kernel.org/r/20231130-vfs-files-fixes-v1-3-e73ca6f4ea83@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Christian Brauner <brauner@kernel.org> diff 3d5cd491 Wed Nov 22 05:27:14 MST 2023 Amir Goldstein <amir73il@gmail.com> fs: create file_write_started() helper Convenience wrapper for sb_write_started(file_inode(inode)->i_sb)), which has a single occurrence in the code right now. Document the false negatives of those helpers, which makes them unusable to assert that sb_start_write() is not held. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-16-amir73il@gmail.com Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christian Brauner <brauner@kernel.org> diff e8e17ee9 Thu Oct 12 11:04:28 MDT 2023 Lorenzo Stoakes <lstoakes@gmail.com> mm: drop the assumption that VM_SHARED always implies writable Patch series "permit write-sealed memfd read-only shared mappings", v4. The man page for fcntl() describing memfd file seals states the following about F_SEAL_WRITE:- Furthermore, trying to create new shared, writable memory-mappings via mmap(2) will also fail with EPERM. With emphasis on 'writable'. In turns out in fact that currently the kernel simply disallows all new shared memory mappings for a memfd with F_SEAL_WRITE applied, rendering this documentation inaccurate. This matters because users are therefore unable to obtain a shared mapping to a memfd after write sealing altogether, which limits their usefulness. This was reported in the discussion thread [1] originating from a bug report [2]. This is a product of both using the struct address_space->i_mmap_writable atomic counter to determine whether writing may be permitted, and the kernel adjusting this counter when any VM_SHARED mapping is performed and more generally implicitly assuming VM_SHARED implies writable. It seems sensible that we should only update this mapping if VM_MAYWRITE is specified, i.e. whether it is possible that this mapping could at any point be written to. If we do so then all we need to do to permit write seals to function as documented is to clear VM_MAYWRITE when mapping read-only. It turns out this functionality already exists for F_SEAL_FUTURE_WRITE - we can therefore simply adapt this logic to do the same for F_SEAL_WRITE. We then hit a chicken and egg situation in mmap_region() where the check for VM_MAYWRITE occurs before we are able to clear this flag. To work around this, perform this check after we invoke call_mmap(), with careful consideration of error paths. Thanks to Andy Lutomirski for the suggestion! [1]:https://lore.kernel.org/all/20230324133646.16101dfa666f253c4715d965@linux-foundation.org/ [2]:https://bugzilla.kernel.org/show_bug.cgi?id=217238 This patch (of 3): There is a general assumption that VMAs with the VM_SHARED flag set are writable. If the VM_MAYWRITE flag is not set, then this is simply not the case. Update those checks which affect the struct address_space->i_mmap_writable field to explicitly test for this by introducing [vma_]is_shared_maywrite() helper functions. This remains entirely conservative, as the lack of VM_MAYWRITE guarantees that the VMA cannot be written to. Link: https://lkml.kernel.org/r/cover.1697116581.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/d978aefefa83ec42d18dfa964ad180dbcde34795.1697116581.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> diff 61d4fb0b Tue Oct 24 16:14:37 MDT 2023 Christian Brauner <brauner@kernel.org> file, i915: fix file reference for mmap_singleton() Today we got a report at [1] for rcu stalls on the i915 testsuite in [2] due to the conversion of files to SLAB_TYPSSAFE_BY_RCU. Afaict, get_file_rcu() goes into an infinite loop trying to carefully verify that i915->gem.mmap_singleton hasn't changed - see the splat below. So I stared at this code to figure out what it actually does. It seems that the i915->gem.mmap_singleton pointer itself never had rcu semantics. The i915->gem.mmap_singleton is replaced in file->f_op->release::singleton_release(): static int singleton_release(struct inode *inode, struct file *file) { struct drm_i915_private *i915 = file->private_data; cmpxchg(&i915->gem.mmap_singleton, file, NULL); drm_dev_put(&i915->drm); return 0; } The cmpxchg() is ordered against a concurrent update of i915->gem.mmap_singleton from mmap_singleton(). IOW, when mmap_singleton() fails to get a reference on i915->gem.mmap_singleton: While mmap_singleton() does rcu_read_lock(); file = get_file_rcu(&i915->gem.mmap_singleton); rcu_read_unlock(); it allocates a new file via anon_inode_getfile() and does smp_store_mb(i915->gem.mmap_singleton, file); So, then what happens in the case of this bug is that at some point fput() is called and drops the file->f_count to zero leaving the pointer in i915->gem.mmap_singleton in tact. Now, there might be delays until file->f_op->release::singleton_release() is called and i915->gem.mmap_singleton is set to NULL. Say concurrently another task hits mmap_singleton() and does: rcu_read_lock(); file = get_file_rcu(&i915->gem.mmap_singleton); rcu_read_unlock(); When get_file_rcu() fails to get a reference via atomic_inc_not_zero() it will try the reload from i915->gem.mmap_singleton expecting it to be NULL, assuming it has comparable semantics as we expect in __fget_files_rcu(). But it hasn't so it reloads the same pointer again, trying the same atomic_inc_not_zero() again and doing so until file->f_op->release::singleton_release() of the old file has been called. So, in contrast to __fget_files_rcu() here we want to not retry when atomic_inc_not_zero() has failed. We only want to retry in case we managed to get a reference but the pointer did change on reload. <3> [511.395679] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: <3> [511.395716] rcu: Tasks blocked on level-1 rcu_node (CPUs 0-9): P6238 <3> [511.395934] rcu: (detected by 16, t=65002 jiffies, g=123977, q=439 ncpus=20) <6> [511.395944] task:i915_selftest state:R running task stack:10568 pid:6238 tgid:6238 ppid:1001 flags:0x00004002 <6> [511.395962] Call Trace: <6> [511.395966] <TASK> <6> [511.395974] ? __schedule+0x3a8/0xd70 <6> [511.395995] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 <6> [511.396003] ? lockdep_hardirqs_on+0xc3/0x140 <6> [511.396013] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 <6> [511.396029] ? get_file_rcu+0x10/0x30 <6> [511.396039] ? get_file_rcu+0x10/0x30 <6> [511.396046] ? i915_gem_object_mmap+0xbc/0x450 [i915] <6> [511.396509] ? i915_gem_mmap+0x272/0x480 [i915] <6> [511.396903] ? mmap_region+0x253/0xb60 <6> [511.396925] ? do_mmap+0x334/0x5c0 <6> [511.396939] ? vm_mmap_pgoff+0x9f/0x1c0 <6> [511.396949] ? rcu_is_watching+0x11/0x50 <6> [511.396962] ? igt_mmap_offset+0xfc/0x110 [i915] <6> [511.397376] ? __igt_mmap+0xb3/0x570 [i915] <6> [511.397762] ? igt_mmap+0x11e/0x150 [i915] <6> [511.398139] ? __trace_bprintk+0x76/0x90 <6> [511.398156] ? __i915_subtests+0xbf/0x240 [i915] <6> [511.398586] ? __pfx___i915_live_setup+0x10/0x10 [i915] <6> [511.399001] ? __pfx___i915_live_teardown+0x10/0x10 [i915] <6> [511.399433] ? __run_selftests+0xbc/0x1a0 [i915] <6> [511.399875] ? i915_live_selftests+0x4b/0x90 [i915] <6> [511.400308] ? i915_pci_probe+0x106/0x200 [i915] <6> [511.400692] ? pci_device_probe+0x95/0x120 <6> [511.400704] ? really_probe+0x164/0x3c0 <6> [511.400715] ? __pfx___driver_attach+0x10/0x10 <6> [511.400722] ? __driver_probe_device+0x73/0x160 <6> [511.400731] ? driver_probe_device+0x19/0xa0 <6> [511.400741] ? __driver_attach+0xb6/0x180 <6> [511.400749] ? __pfx___driver_attach+0x10/0x10 <6> [511.400756] ? bus_for_each_dev+0x77/0xd0 <6> [511.400770] ? bus_add_driver+0x114/0x210 <6> [511.400781] ? driver_register+0x5b/0x110 <6> [511.400791] ? i915_init+0x23/0xc0 [i915] <6> [511.401153] ? __pfx_i915_init+0x10/0x10 [i915] <6> [511.401503] ? do_one_initcall+0x57/0x270 <6> [511.401515] ? rcu_is_watching+0x11/0x50 <6> [511.401521] ? kmalloc_trace+0xa3/0xb0 <6> [511.401532] ? do_init_module+0x5f/0x210 <6> [511.401544] ? load_module+0x1d00/0x1f60 <6> [511.401581] ? init_module_from_file+0x86/0xd0 <6> [511.401590] ? init_module_from_file+0x86/0xd0 <6> [511.401613] ? idempotent_init_module+0x17c/0x230 <6> [511.401639] ? __x64_sys_finit_module+0x56/0xb0 <6> [511.401650] ? do_syscall_64+0x3c/0x90 <6> [511.401659] ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8 <6> [511.401684] </TASK> Link: [1]: https://lore.kernel.org/intel-gfx/SJ1PR11MB6129CB39EED831784C331BAFB9DEA@SJ1PR11MB6129.namprd11.prod.outlook.com Link: [2]: https://intel-gfx-ci.01.org/tree/linux-next/next-20231013/bat-dg2-11/igt@i915_selftest@live@mman.html#dmesg-warnings10963 Cc: Jann Horn <jannh@google.com>, Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20231025-formfrage-watscheln-84526cd3bd7d@brauner Signed-off-by: Christian Brauner <brauner@kernel.org> diff 61d4fb0b Tue Oct 24 16:14:37 MDT 2023 Christian Brauner <brauner@kernel.org> file, i915: fix file reference for mmap_singleton() Today we got a report at [1] for rcu stalls on the i915 testsuite in [2] due to the conversion of files to SLAB_TYPSSAFE_BY_RCU. Afaict, get_file_rcu() goes into an infinite loop trying to carefully verify that i915->gem.mmap_singleton hasn't changed - see the splat below. So I stared at this code to figure out what it actually does. It seems that the i915->gem.mmap_singleton pointer itself never had rcu semantics. The i915->gem.mmap_singleton is replaced in file->f_op->release::singleton_release(): static int singleton_release(struct inode *inode, struct file *file) { struct drm_i915_private *i915 = file->private_data; cmpxchg(&i915->gem.mmap_singleton, file, NULL); drm_dev_put(&i915->drm); return 0; } The cmpxchg() is ordered against a concurrent update of i915->gem.mmap_singleton from mmap_singleton(). IOW, when mmap_singleton() fails to get a reference on i915->gem.mmap_singleton: While mmap_singleton() does rcu_read_lock(); file = get_file_rcu(&i915->gem.mmap_singleton); rcu_read_unlock(); it allocates a new file via anon_inode_getfile() and does smp_store_mb(i915->gem.mmap_singleton, file); So, then what happens in the case of this bug is that at some point fput() is called and drops the file->f_count to zero leaving the pointer in i915->gem.mmap_singleton in tact. Now, there might be delays until file->f_op->release::singleton_release() is called and i915->gem.mmap_singleton is set to NULL. Say concurrently another task hits mmap_singleton() and does: rcu_read_lock(); file = get_file_rcu(&i915->gem.mmap_singleton); rcu_read_unlock(); When get_file_rcu() fails to get a reference via atomic_inc_not_zero() it will try the reload from i915->gem.mmap_singleton expecting it to be NULL, assuming it has comparable semantics as we expect in __fget_files_rcu(). But it hasn't so it reloads the same pointer again, trying the same atomic_inc_not_zero() again and doing so until file->f_op->release::singleton_release() of the old file has been called. So, in contrast to __fget_files_rcu() here we want to not retry when atomic_inc_not_zero() has failed. We only want to retry in case we managed to get a reference but the pointer did change on reload. <3> [511.395679] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: <3> [511.395716] rcu: Tasks blocked on level-1 rcu_node (CPUs 0-9): P6238 <3> [511.395934] rcu: (detected by 16, t=65002 jiffies, g=123977, q=439 ncpus=20) <6> [511.395944] task:i915_selftest state:R running task stack:10568 pid:6238 tgid:6238 ppid:1001 flags:0x00004002 <6> [511.395962] Call Trace: <6> [511.395966] <TASK> <6> [511.395974] ? __schedule+0x3a8/0xd70 <6> [511.395995] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 <6> [511.396003] ? lockdep_hardirqs_on+0xc3/0x140 <6> [511.396013] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 <6> [511.396029] ? get_file_rcu+0x10/0x30 <6> [511.396039] ? get_file_rcu+0x10/0x30 <6> [511.396046] ? i915_gem_object_mmap+0xbc/0x450 [i915] <6> [511.396509] ? i915_gem_mmap+0x272/0x480 [i915] <6> [511.396903] ? mmap_region+0x253/0xb60 <6> [511.396925] ? do_mmap+0x334/0x5c0 <6> [511.396939] ? vm_mmap_pgoff+0x9f/0x1c0 <6> [511.396949] ? rcu_is_watching+0x11/0x50 <6> [511.396962] ? igt_mmap_offset+0xfc/0x110 [i915] <6> [511.397376] ? __igt_mmap+0xb3/0x570 [i915] <6> [511.397762] ? igt_mmap+0x11e/0x150 [i915] <6> [511.398139] ? __trace_bprintk+0x76/0x90 <6> [511.398156] ? __i915_subtests+0xbf/0x240 [i915] <6> [511.398586] ? __pfx___i915_live_setup+0x10/0x10 [i915] <6> [511.399001] ? __pfx___i915_live_teardown+0x10/0x10 [i915] <6> [511.399433] ? __run_selftests+0xbc/0x1a0 [i915] <6> [511.399875] ? i915_live_selftests+0x4b/0x90 [i915] <6> [511.400308] ? i915_pci_probe+0x106/0x200 [i915] <6> [511.400692] ? pci_device_probe+0x95/0x120 <6> [511.400704] ? really_probe+0x164/0x3c0 <6> [511.400715] ? __pfx___driver_attach+0x10/0x10 <6> [511.400722] ? __driver_probe_device+0x73/0x160 <6> [511.400731] ? driver_probe_device+0x19/0xa0 <6> [511.400741] ? __driver_attach+0xb6/0x180 <6> [511.400749] ? __pfx___driver_attach+0x10/0x10 <6> [511.400756] ? bus_for_each_dev+0x77/0xd0 <6> [511.400770] ? bus_add_driver+0x114/0x210 <6> [511.400781] ? driver_register+0x5b/0x110 <6> [511.400791] ? i915_init+0x23/0xc0 [i915] <6> [511.401153] ? __pfx_i915_init+0x10/0x10 [i915] <6> [511.401503] ? do_one_initcall+0x57/0x270 <6> [511.401515] ? rcu_is_watching+0x11/0x50 <6> [511.401521] ? kmalloc_trace+0xa3/0xb0 <6> [511.401532] ? do_init_module+0x5f/0x210 <6> [511.401544] ? load_module+0x1d00/0x1f60 <6> [511.401581] ? init_module_from_file+0x86/0xd0 <6> [511.401590] ? init_module_from_file+0x86/0xd0 <6> [511.401613] ? idempotent_init_module+0x17c/0x230 <6> [511.401639] ? __x64_sys_finit_module+0x56/0xb0 <6> [511.401650] ? do_syscall_64+0x3c/0x90 <6> [511.401659] ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8 <6> [511.401684] </TASK> Link: [1]: https://lore.kernel.org/intel-gfx/SJ1PR11MB6129CB39EED831784C331BAFB9DEA@SJ1PR11MB6129.namprd11.prod.outlook.com Link: [2]: https://intel-gfx-ci.01.org/tree/linux-next/next-20231013/bat-dg2-11/igt@i915_selftest@live@mman.html#dmesg-warnings10963 Cc: Jann Horn <jannh@google.com>, Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20231025-formfrage-watscheln-84526cd3bd7d@brauner Signed-off-by: Christian Brauner <brauner@kernel.org> diff 61d4fb0b Tue Oct 24 16:14:37 MDT 2023 Christian Brauner <brauner@kernel.org> file, i915: fix file reference for mmap_singleton() Today we got a report at [1] for rcu stalls on the i915 testsuite in [2] due to the conversion of files to SLAB_TYPSSAFE_BY_RCU. Afaict, get_file_rcu() goes into an infinite loop trying to carefully verify that i915->gem.mmap_singleton hasn't changed - see the splat below. So I stared at this code to figure out what it actually does. It seems that the i915->gem.mmap_singleton pointer itself never had rcu semantics. The i915->gem.mmap_singleton is replaced in file->f_op->release::singleton_release(): static int singleton_release(struct inode *inode, struct file *file) { struct drm_i915_private *i915 = file->private_data; cmpxchg(&i915->gem.mmap_singleton, file, NULL); drm_dev_put(&i915->drm); return 0; } The cmpxchg() is ordered against a concurrent update of i915->gem.mmap_singleton from mmap_singleton(). IOW, when mmap_singleton() fails to get a reference on i915->gem.mmap_singleton: While mmap_singleton() does rcu_read_lock(); file = get_file_rcu(&i915->gem.mmap_singleton); rcu_read_unlock(); it allocates a new file via anon_inode_getfile() and does smp_store_mb(i915->gem.mmap_singleton, file); So, then what happens in the case of this bug is that at some point fput() is called and drops the file->f_count to zero leaving the pointer in i915->gem.mmap_singleton in tact. Now, there might be delays until file->f_op->release::singleton_release() is called and i915->gem.mmap_singleton is set to NULL. Say concurrently another task hits mmap_singleton() and does: rcu_read_lock(); file = get_file_rcu(&i915->gem.mmap_singleton); rcu_read_unlock(); When get_file_rcu() fails to get a reference via atomic_inc_not_zero() it will try the reload from i915->gem.mmap_singleton expecting it to be NULL, assuming it has comparable semantics as we expect in __fget_files_rcu(). But it hasn't so it reloads the same pointer again, trying the same atomic_inc_not_zero() again and doing so until file->f_op->release::singleton_release() of the old file has been called. So, in contrast to __fget_files_rcu() here we want to not retry when atomic_inc_not_zero() has failed. We only want to retry in case we managed to get a reference but the pointer did change on reload. <3> [511.395679] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: <3> [511.395716] rcu: Tasks blocked on level-1 rcu_node (CPUs 0-9): P6238 <3> [511.395934] rcu: (detected by 16, t=65002 jiffies, g=123977, q=439 ncpus=20) <6> [511.395944] task:i915_selftest state:R running task stack:10568 pid:6238 tgid:6238 ppid:1001 flags:0x00004002 <6> [511.395962] Call Trace: <6> [511.395966] <TASK> <6> [511.395974] ? __schedule+0x3a8/0xd70 <6> [511.395995] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 <6> [511.396003] ? lockdep_hardirqs_on+0xc3/0x140 <6> [511.396013] ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 <6> [511.396029] ? get_file_rcu+0x10/0x30 <6> [511.396039] ? get_file_rcu+0x10/0x30 <6> [511.396046] ? i915_gem_object_mmap+0xbc/0x450 [i915] <6> [511.396509] ? i915_gem_mmap+0x272/0x480 [i915] <6> [511.396903] ? mmap_region+0x253/0xb60 <6> [511.396925] ? do_mmap+0x334/0x5c0 <6> [511.396939] ? vm_mmap_pgoff+0x9f/0x1c0 <6> [511.396949] ? rcu_is_watching+0x11/0x50 <6> [511.396962] ? igt_mmap_offset+0xfc/0x110 [i915] <6> [511.397376] ? __igt_mmap+0xb3/0x570 [i915] <6> [511.397762] ? igt_mmap+0x11e/0x150 [i915] <6> [511.398139] ? __trace_bprintk+0x76/0x90 <6> [511.398156] ? __i915_subtests+0xbf/0x240 [i915] <6> [511.398586] ? __pfx___i915_live_setup+0x10/0x10 [i915] <6> [511.399001] ? __pfx___i915_live_teardown+0x10/0x10 [i915] <6> [511.399433] ? __run_selftests+0xbc/0x1a0 [i915] <6> [511.399875] ? i915_live_selftests+0x4b/0x90 [i915] <6> [511.400308] ? i915_pci_probe+0x106/0x200 [i915] <6> [511.400692] ? pci_device_probe+0x95/0x120 <6> [511.400704] ? really_probe+0x164/0x3c0 <6> [511.400715] ? __pfx___driver_attach+0x10/0x10 <6> [511.400722] ? __driver_probe_device+0x73/0x160 <6> [511.400731] ? driver_probe_device+0x19/0xa0 <6> [511.400741] ? __driver_attach+0xb6/0x180 <6> [511.400749] ? __pfx___driver_attach+0x10/0x10 <6> [511.400756] ? bus_for_each_dev+0x77/0xd0 <6> [511.400770] ? bus_add_driver+0x114/0x210 <6> [511.400781] ? driver_register+0x5b/0x110 <6> [511.400791] ? i915_init+0x23/0xc0 [i915] <6> [511.401153] ? __pfx_i915_init+0x10/0x10 [i915] <6> [511.401503] ? do_one_initcall+0x57/0x270 <6> [511.401515] ? rcu_is_watching+0x11/0x50 <6> [511.401521] ? kmalloc_trace+0xa3/0xb0 <6> [511.401532] ? do_init_module+0x5f/0x210 <6> [511.401544] ? load_module+0x1d00/0x1f60 <6> [511.401581] ? init_module_from_file+0x86/0xd0 <6> [511.401590] ? init_module_from_file+0x86/0xd0 <6> [511.401613] ? idempotent_init_module+0x17c/0x230 <6> [511.401639] ? __x64_sys_finit_module+0x56/0xb0 <6> [511.401650] ? do_syscall_64+0x3c/0x90 <6> [511.401659] ? entry_SYSCALL_64_after_hwframe+0x6e/0xd8 <6> [511.401684] </TASK> Link: [1]: https://lore.kernel.org/intel-gfx/SJ1PR11MB6129CB39EED831784C331BAFB9DEA@SJ1PR11MB6129.namprd11.prod.outlook.com Link: [2]: https://intel-gfx-ci.01.org/tree/linux-next/next-20231013/bat-dg2-11/igt@i915_selftest@live@mman.html#dmesg-warnings10963 Cc: Jann Horn <jannh@google.com>, Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20231025-formfrage-watscheln-84526cd3bd7d@brauner Signed-off-by: Christian Brauner <brauner@kernel.org> |
Completed in 941 milliseconds