Group corruption check will access memory of grp and will trigger kernel crash if grp is NULL. So do NULL check before corruption check. Fixes: 5354b2af3406 ("ext4: allow ext4_get_group_info() to fail") Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx> --- fs/ext4/mballoc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 3e34e37392fb..556b7cd27f76 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2553,7 +2553,7 @@ static bool ext4_mb_good_group(struct ext4_allocation_context *ac, BUG_ON(cr < CR_POWER2_ALIGNED || cr >= EXT4_MB_NUM_CRS); - if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp) || !grp)) + if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) return false; free = grp->bb_free; -- 2.30.0