4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
commit 10479e2dea83d4c421ad05dfc55d918aa8dfc0cd upstream.
In some circumstances, _alloc_read_agf can return an error code of zero
but also a null AGF buffer pointer. Check for this and jump out.
Fixes-coverity-id: 1415250
Fixes-coverity-id: 1415320
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/xfs/libxfs/xfs_refcount.c | 4 ++++
fs/xfs/xfs_reflink.c | 2 ++
2 files changed, 6 insertions(+)
--- a/fs/xfs/libxfs/xfs_refcount.c
+++ b/fs/xfs/libxfs/xfs_refcount.c
@@ -1640,6 +1640,10 @@ xfs_refcount_recover_cow_leftovers(
error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
if (error)
goto out_trans;
+ if (!agbp) {
+ error = -ENOMEM;
+ goto out_trans;
+ }
cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
/* Find all the leftover CoW staging extents. */
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -169,6 +169,8 @@ xfs_reflink_find_shared(
error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
if (error)
return error;
+ if (!agbp)
+ return -ENOMEM;
cur = xfs_refcountbt_init_cursor(mp, NULL, agbp, agno, NULL);