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From: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
To: Kemeng Shi <shikemeng@huaweicloud.com>,
	tytso@mit.edu, adilger.kernel@dilger.ca, ojaswin@linux.ibm.com,
	linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: shikemeng@huaweicloud.com
Subject: Re: [PATCH 01/10] ext4: correct grp validation in ext4_mb_good_group
Date: Fri, 21 Jul 2023 20:52:49 +0530	[thread overview]
Message-ID: <87iladl25y.fsf@doe.com> (raw)
In-Reply-To: <20230721171007.2065423-2-shikemeng@huaweicloud.com>

Kemeng Shi <shikemeng@huaweicloud.com> 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@huaweicloud.com>
> ---
>  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

  reply	other threads:[~2023-07-21 15:23 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-21 17:09 [PATCH 00/10] A few fixes and cleanups to mballoc Kemeng Shi
2023-07-21 15:55 ` Ritesh Harjani
2023-07-25  2:09   ` Kemeng Shi
2023-07-21 17:09 ` [PATCH 01/10] ext4: correct grp validation in ext4_mb_good_group Kemeng Shi
2023-07-21 15:22   ` Ritesh Harjani [this message]
2023-07-21 17:09 ` [PATCH 02/10] ext4: avoid potential data overflow in next_linear_group Kemeng Shi
2023-07-21 15:26   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 03/10] ext4: return found group directly in ext4_mb_choose_next_group_p2_aligned Kemeng Shi
2023-07-21 15:31   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 04/10] ext4: use is_power_of_2 helper in ext4_mb_regular_allocator Kemeng Shi
2023-07-21 15:37   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 05/10] ext4: remove unnecessary return for void function Kemeng Shi
2023-07-21 15:43   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 06/10] ext4: replace the traditional ternary conditional operator with with max()/min() Kemeng Shi
2023-07-21 15:44   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 07/10] ext4: remove unused ext4_{set}/{clear}_bit_atomic Kemeng Shi
2023-07-21 15:45   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 08/10] ext4: return found group directly in ext4_mb_choose_next_group_goal_fast Kemeng Shi
2023-07-21 15:45   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 09/10] ext4: return found group directly in ext4_mb_choose_next_group_best_avail Kemeng Shi
2023-07-21 15:48   ` Ritesh Harjani
2023-07-21 17:10 ` [PATCH 10/10] ext4: correct some stale comment of criteria Kemeng Shi
2023-07-21 15:49   ` Ritesh Harjani

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