6.12-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
commit 07eae0fa67ca4bbb199ad85645e0f9dfaef931cd upstream.
Commit 32dd4f9c506b ("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: 32dd4f9c506b ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/xfs/xfs_buf.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -663,9 +663,8 @@ 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)