xfs: check _alloc_read_agf buffer pointer before using
Source kernel commit: 10479e2dea83d4c421ad05dfc55d918aa8dfc0cd
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@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
diff --git a/libxfs/xfs_refcount.c b/libxfs/xfs_refcount.c
index 52ec20c..3e0c815 100644
--- a/libxfs/xfs_refcount.c
+++ b/libxfs/xfs_refcount.c
@@ -1637,6 +1637,10 @@
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. */
