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xfs: check for dead buffers in xfs_buf_find_insert

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Commit 32dd4f9c50 ("xfs: remove a superflous hash lookup when inserting
new buffers") converted xfs_buf_find_insert to use
rhashtable_lookup_get_insert_fast and thus an operation that returns the
existing buffer when an insert would duplicate the hash key.  But this
code path misses the check for a buffer with a reference count of zero,
which could lead to reusing an about to be freed buffer.  Fix this by
using the same atomic_inc_not_zero pattern as xfs_buf_insert.

Fixes: 32dd4f9c50 ("xfs: remove a superflous hash lookup when inserting new buffers")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: stable@vger.kernel.org # v6.0
Signed-off-by: Carlos Maiolino <cem@kernel.org>
This commit is contained in:
Christoph Hellwig
2025-01-16 07:01:41 +01:00
committed by Carlos Maiolino
parent 4e35be63c4
commit 07eae0fa67
1 changed files with 1 additions and 2 deletions
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3
fs/xfs/xfs_buf.c
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@@ -655,9 +655,8 @@ xfs_buf_find_insert(
spin_unlock(&bch->bc_lock);
goto out_free_buf;
}
if (bp) {
if (bp && atomic_inc_not_zero(&bp->b_hold)) {
/* found an existing buffer */
atomic_inc(&bp->b_hold);
spin_unlock(&bch->bc_lock);
error = xfs_buf_find_lock(bp, flags);
if (error)