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| author | Brian Foster <bfoster@redhat.com> | 2019-04-12 16:39:19 +0200 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2019-04-15 03:15:56 +0200 |
| commit | 4d09807f20462d6edf04f6e98d3d47bcdf7a5e2f (patch) | |
| tree | a9cc42a695f26db2fee2fa03fe1749bacd5cefb8 | |
| parent | Linux 5.1-rc5 (diff) | |
| download | linux-4d09807f20462d6edf04f6e98d3d47bcdf7a5e2f.tar.xz linux-4d09807f20462d6edf04f6e98d3d47bcdf7a5e2f.zip | |
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>
| -rw-r--r-- | fs/xfs/xfs_buf_item.c | 4 |
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); } |