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From: Guoqing Jiang <guoqing.jiang@linux.dev>
To: Song Liu <song@kernel.org>, lwt105 <3061522931@qq.com>
Cc: linux-raid <linux-raid@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drivers:md:fix a potential use-after-free bug
Date: Tue, 17 Aug 2021 15:47:16 +0800	[thread overview]
Message-ID: <6b4c8938-a8a9-1a14-87bd-f30e4eda2b3d@linux.dev> (raw)
In-Reply-To: <CAPhsuW7cC+d5mhNjJb0AiHDKCUb5WzYPNzZ5UPOSScdtFuNzww@mail.gmail.com>



On 8/14/21 12:16 AM, Song Liu wrote:
> On Thu, Aug 12, 2021 at 8:46 PM lwt105<3061522931@qq.com>  wrote:
>> In line 2867, "raid5_release_stripe(sh);" drops the reference to sh and
>> may cause sh to be released. However, sh is subsequently used in lines
>> 2869 "if (sh->batch_head && sh != sh->batch_head)". This may result in an
>> use-after-free bug.
>>
>> It can be fixed by moving "raid5_release_stripe(sh);" to the bottom of
>> the function.
>>
>> Signed-off-by: lwt105<3061522931@qq.com>
> The fix looks reasonable.

I am not sure this is needed unless there is real calltrace to prove it. 
Because raid5_release_stripe
doesn't mean it will release the sh's memory,  pls see the comment 
before clear_batch_ready in
handle_stripe, and the path handle_stripe -> handle_stripe_clean_event 
-> break_stripe_batch_list.

Thanks,
Guoqing

  reply	other threads:[~2021-08-17  7:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <tencent_888910D6F881B3D8BD9C3DFED667A5009806@qq.com>
2021-08-13 16:16 ` Song Liu
2021-08-17  7:47   ` Guoqing Jiang [this message]
2022-07-28 11:39 Wentao_Liang
2022-07-28  5:55 ` Song Liu

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