autofs: use wake_up() instead of wake_up_interruptible(()

In autofs_wait_release() wake_up() is used to wake up processes waiting
on a mount callback to complete which matches the wait_event_killable()
in autofs_wait().

But in autofs_catatonic_mode() the wake_up_interruptible() was not also
changed at the time autofs_wait_release() was changed.

Signed-off-by: Ian Kent <raven@themaw.net>
Message-Id: <169112719813.7590.4971499386839952992.stgit@donald.themaw.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>

autofs: fix memory leak of waitqueues in autofs_catatonic_mode

Syzkaller reports a memory leak:

BUG: memory leak
unreferenced object 0xffff88810b279e00 (size 96):
comm "syz-executor399", pid 3631, jiffies 4294964921 (age 23.870s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 08 9e 27 0b 81 88 ff ff ..........'.....
08 9e 27 0b 81 88 ff ff 00 00 00 00 00 00 00 00 ..'.............
backtrace:
[<ffffffff814cfc90>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
[<ffffffff81bb75ca>] kmalloc include/linux/slab.h:576 [inline]
[<ffffffff81bb75ca>] autofs_wait+0x3fa/0x9a0 fs/autofs/waitq.c:378
[<ffffffff81bb88a7>] autofs_do_expire_multi+0xa7/0x3e0 fs/autofs/expire.c:593
[<ffffffff81bb8c33>] autofs_expire_multi+0x53/0x80 fs/autofs/expire.c:619
[<ffffffff81bb6972>] autofs_root_ioctl_unlocked+0x322/0x3b0 fs/autofs/root.c:897
[<ffffffff81bb6a95>] autofs_root_ioctl+0x25/0x30 fs/autofs/root.c:910
[<ffffffff81602a9c>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff81602a9c>] __do_sys_ioctl fs/ioctl.c:870 [inline]
[<ffffffff81602a9c>] __se_sys_ioctl fs/ioctl.c:856 [inline]
[<ffffffff81602a9c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
[<ffffffff84608225>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84608225>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

autofs_wait_queue structs should be freed if their wait_ctr becomes zero.
Otherwise they will be lost.

In this case an AUTOFS_IOC_EXPIRE_MULTI ioctl is done, then a new
waitqueue struct is allocated in autofs_wait(), its initial wait_ctr
equals 2. After that wait_event_killable() is interrupted (it returns
-ERESTARTSYS), so that 'wq->name.name == NULL' condition may be not
satisfied. Actually, this condition can be satisfied when
autofs_wait_release() or autofs_catatonic_mode() is called and, what is
also important, wait_ctr is decremented in those places. Upon the exit of
autofs_wait(), wait_ctr is decremented to 1. Then the unmounting process
begins: kill_sb calls autofs_catatonic_mode(), which should have freed the
waitqueues, but it only decrements its usage counter to zero which is not
a correct behaviour.

edit:imk
This description is of course not correct. The umount performed as a result
of an expire is a umount of a mount that has been automounted, it's not the
autofs mount itself. They happen independently, usually after everything
mounted within the autofs file system has been expired away. If everything
hasn't been expired away the automount daemon can still exit leaving mounts
in place. But expires done in both cases will result in a notification that
calls autofs_wait_release() with a result status. The problem case is the
summary execution of of the automount daemon. In this case any waiting
processes won't be woken up until either they are terminated or the mount
is umounted.
end edit: imk

So in catatonic mode we should free waitqueues which counter becomes zero.

edit: imk
Initially I was concerned that the calling of autofs_wait_release() and
autofs_catatonic_mode() was not mutually exclusive but that can't be the
case (obviously) because the queue entry (or entries) is removed from the
list when either of these two functions are called. Consequently the wait
entry will be freed by only one of these functions or by the woken process
in autofs_wait() depending on the order of the calls.
end edit: imk

Reported-by: syzbot+5e53f70e69ff0c0a1c0c@syzkaller.appspotmail.com
Suggested-by: Takeshi Misawa <jeliantsurux@gmail.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: autofs@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Message-Id: <169112719161.7590.6700123246297365841.stgit@donald.themaw.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>

autofs: fix wait name hash calculation in autofs_wait()

There's a mistake in commit 2be7828c9fefc ("get rid of autofs_getpath()")
that affects kernels from v5.13.0, basically missed because of me not
fully testing the change for Al.

The problem is that the hash calculation for the wait name qstr hasn't
been updated to account for the change to use dentry_path_raw(). This
prevents the correct matching an existing wait resulting in multiple
notifications being sent to the daemon for the same mount which must
not occur.

The problem wasn't discovered earlier because it only occurs when
multiple processes trigger a request for the same mount concurrently
so it only shows up in more aggressive testing.

Fixes: 2be7828c9fefc ("get rid of autofs_getpath()")
Cc: stable@vger.kernel.org
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

get rid of autofs_getpath()

allow wq->name.name to point not at the beginning of the object containing
the string, with wq->offset telling how far into it we are. Then we can
bloody well just use dentry_path_raw() instead of autofs_getpath() -
the only real difference is that dentry_path_raw() puts the result into
the end of buffer and returns where it starts.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

autofs: use __kernel_write() for the autofs pipe writing

autofs got broken in some configurations by commit 13c164b1a186
("autofs: switch to kernel_write") because there is now an extra LSM
permission check done by security_file_permission() in rw_verify_area().

autofs is one if the few places that really does want the much more
limited __kernel_write(), because the write is an internal kernel one
that shouldn't do any user permission checks (it also doesn't need the
file_start_write/file_end_write logic, since it's just a pipe).

There are a couple of other cases like that - accounting, core dumping,
and splice - but autofs stands out because it can be built as a module.

As a result, we need to export this internal __kernel_write() function
again.

We really don't want any other module to use this, but we don't have a
"EXPORT_SYMBOL_FOR_AUTOFS_ONLY()". But we can mark it GPL-only to at
least approximate that "internal use only" for licensing.

While in this area, make autofs pass in NULL for the file position
pointer, since it's always a pipe, and we now use a NULL file pointer
for streaming file descriptors (see file_ppos() and commit 438ab720c675:
"vfs: pass ppos=NULL to .read()/.write() of FMODE_STREAM files")

This effectively reverts commits 9db977522449 ("fs: unexport
__kernel_write") and 13c164b1a186 ("autofs: switch to kernel_write").

Fixes: 13c164b1a186 ("autofs: switch to kernel_write")
Reported-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

autofs: switch to kernel_write

While pipes don't really need sb_writers projection, __kernel_write is an
interface better kept private, and the additional rw_verify_area does not
hurt here.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ian Kent <raven@themaw.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 83

Based on 1 normalized pattern(s):

this file is part of the linux kernel and is made available under
the terms of the gnu general public license version 2 or at your
option any later version incorporated herein by reference

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 18 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520075211.321157221@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

autofs: change catatonic setting to a bit flag

Change the superblock info. catatonic setting to be part of a flags bit
field.

Link: http://lkml.kernel.org/r/154296973142.9889.17275721668508589639.stgit@pluto-themaw-net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

autofs: small cleanup in autofs_getpath()

We don't set "*name" so it's slightly nicer to just pass "name" instead
of "&name".

Link: http://lkml.kernel.org/r/20180531064736.lnisb55eajwjynvk@kili.mountain
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

autofs: clean up includes

Remove includes that aren't needed from autofs (and fs/compat_ioctl.c).

Link: http://lkml.kernel.org/r/152635085258.5968.9743527195522188148.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

autofs: copy autofs4 to autofs

Copy source files from the autofs4 directory to the autofs directory.

Link: http://lkml.kernel.org/r/152626705013.28589.931913083997578251.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sparse pointer use of zero as null

Get rid of sparse related warnings from places that use integer as NULL
pointer.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] autofs4: panic after mount fail

Resolve the panic on failed mount of an autofs filesystem originally
reported by Mao Bibo.

It addresses two issues that happen after the mount fail. The first a NULL
pointer reference to a field (pipe) in the autofs superblock info structure
and second the lack of super block cleanup by the autofs and autofs4
modules.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] kfree cleanup: fs

This is the fs/ part of the big kfree cleanup patch.

Remove pointless checks for NULL prior to calling kfree() in fs/.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!