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authorBrian Foster <bfoster@redhat.com>2019-04-12 17:39:19 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2019-04-15 04:15:56 +0300
commit4d09807f20462d6edf04f6e98d3d47bcdf7a5e2f (patch)
treea9cc42a695f26db2fee2fa03fe1749bacd5cefb8 /fs/xfs
parentdc4060a5dc2557e6b5aa813bf5b73677299d62d2 (diff)
downloadlinux-4d09807f20462d6edf04f6e98d3d47bcdf7a5e2f.tar.xz
xfs: fix use after free in buf log item unlock assert
The xfs_buf_log_item ->iop_unlock() callback asserts that the buffer is unlocked when either non-stale or aborted. This assert occurs after the bli refcount has been dropped and the log item potentially freed. The aborted check is thus a potential use after free. This problem has been reproduced with KASAN enabled via generic/475. Fix up xfs_buf_item_unlock() to query aborted state before the bli reference is dropped to prevent a potential use after free. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_buf_item.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 010db5f8fb00..65b32acfa0f6 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -605,6 +605,8 @@ xfs_buf_item_unlock(
#if defined(DEBUG) || defined(XFS_WARN)
bool ordered = bip->bli_flags & XFS_BLI_ORDERED;
bool dirty = bip->bli_flags & XFS_BLI_DIRTY;
+ bool aborted = test_bit(XFS_LI_ABORTED,
+ &lip->li_flags);
#endif
trace_xfs_buf_item_unlock(bip);
@@ -633,7 +635,7 @@ xfs_buf_item_unlock(
released = xfs_buf_item_put(bip);
if (hold || (stale && !released))
return;
- ASSERT(!stale || test_bit(XFS_LI_ABORTED, &lip->li_flags));
+ ASSERT(!stale || aborted);
xfs_buf_relse(bp);
}