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0a69b6b3 |
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20-Mar-2024 |
Carlos Maiolino <cem@kernel.org> |
tmpfs: fix race on handling dquot rbtree A syzkaller reproducer found a race while attempting to remove dquot information from the rb tree. Fetching the rb_tree root node must also be protected by the dqopt->dqio_sem, otherwise, giving the right timing, shmem_release_dquot() will trigger a warning because it couldn't find a node in the tree, when the real reason was the root node changing before the search starts: Thread 1 Thread 2 - shmem_release_dquot() - shmem_{acquire,release}_dquot() - fetch ROOT - Fetch ROOT - acquire dqio_sem - wait dqio_sem - do something, triger a tree rebalance - release dqio_sem - acquire dqio_sem - start searching for the node, but from the wrong location, missing the node, and triggering a warning. Link: https://lkml.kernel.org/r/20240320124011.398847-1-cem@kernel.org Fixes: eafc474e2029 ("shmem: prepare shmem quota infrastructure") Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reported-by: Ubisectech Sirius <bugreport@ubisectech.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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eafc474e |
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25-Jul-2023 |
Carlos Maiolino <cem@kernel.org> |
shmem: prepare shmem quota infrastructure Add new shmem quota format, its quota_format_ops together with dquot_operations Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Message-Id: <20230725144510.253763-5-cem@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
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