Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx> writes:
> 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>
> ---
> 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 3ab37533349f..90ffabac100b 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2554,7 +2554,7 @@ 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 (!grp || unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
maybe like below?
if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
-ritesh
> return false;
>
> free = grp->bb_free;
> --
> 2.30.0
