From 245759d987b617d183061db6ab8886ebb5cc78e9 Mon Sep 17 00:00:00 2001 From: Kemeng Shi Date: Tue, 1 Aug 2023 22:31:55 +0800 Subject: [PATCH] ext4: correct grp validation in ext4_mb_good_group [ Upstream commit a9ce5993a0f5c0887c8a1b4ffa3b8046fbcfdc93 ] 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 Reviewed-by: Ritesh Harjani (IBM) Link: https://lore.kernel.org/r/20230801143204.2284343-2-shikemeng@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- 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 3a7192884671..2f6ed59d81f0 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2103,7 +2103,7 @@ static bool ext4_mb_good_group(struct ext4_allocation_context *ac, BUG_ON(cr < 0 || cr >= 4); - if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp) || !grp)) + if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))) return false; free = grp->bb_free;