xfs: fix uninitialized variable access

If the end position of a GETFSMAP query overlaps an allocated space and
we're using the free space info to generate fsmap info, the akeys
information gets fed into the fsmap formatter with bad results.
Zero-init the space.

Reported-by: syzbot+090ae72d552e6bd93cfe@syzkaller.appspotmail.com
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 120d284a03fe4b607df60101bb3a661dad59f913..59e7d1a14b67243d118dce25e51e7adc6d58294c 100644 (file)
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -761,6 +761,7 @@ xfs_getfsmap_datadev_bnobt(
 {
        struct xfs_alloc_rec_incore     akeys[2];
 
+       memset(akeys, 0, sizeof(akeys));
        info->missing_owner = XFS_FMR_OWN_UNKNOWN;
        return __xfs_getfsmap_datadev(tp, keys, info,
                        xfs_getfsmap_datadev_bnobt_query, &akeys[0]);