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Message-ID: <e93da9cc-d92d-34c8-a820-1f2b211caf53@huaweicloud.com>
Date:   Thu, 25 May 2023 21:55:40 +0800
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Subject: Re: [PATCH 1/3] md/raid10: fix null-ptr-deref of mreplace in
 raid10_sync_request
To:     Yu Kuai <yukuai1@huaweicloud.com>, linan666@huaweicloud.com,
        song@kernel.org, shli@fb.com, allenpeng@synology.com,
        alexwu@synology.com, bingjingc@synology.com, neilb@suse.de
Cc:     linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
        yi.zhang@huawei.com, houtao1@huawei.com, yangerkun@huawei.com,
        "yukuai (C)" <yukuai3@huawei.com>
References: <20230522115449.2203939-1-linan666@huaweicloud.com>
 <20230522115449.2203939-2-linan666@huaweicloud.com>
 <6c2d40de-7b8c-d84d-d9a2-7c5dce7471aa@huaweicloud.com>
From:   Li Nan <linan666@huaweicloud.com>
In-Reply-To: <6c2d40de-7b8c-d84d-d9a2-7c5dce7471aa@huaweicloud.com>
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在 2023/5/22 21:01, Yu Kuai 写道:
> Hi,
> 
> 在 2023/05/22 19:54, linan666@huaweicloud.com 写道:
>> From: Li Nan <linan122@huawei.com>
>>
>> need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
>> will be deref later. However, the latter check of mreplace might set
>> mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this 
>> time.
>>
>> Fix it by merging two checks into one. And replace 'need_replace' with
>> 'mreplace' because their values are always the same.
>>
>> Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new 
>> added disk faulty")
>> Signed-off-by: Li Nan <linan122@huawei.com>
>> ---
>>   drivers/md/raid10.c | 13 +++++--------
>>   1 file changed, 5 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index 4fcfcb350d2b..e21502c03b45 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev 
>> *mddev, sector_t sector_nr,
>>               int must_sync;
>>               int any_working;
>>               int need_recover = 0;
> 
> need_recover can be removed as well. Otherwise, this patch looks good to
> me.
> 

I agree. Let me improve this in v2.
-- 
Thanks,
Nan