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Message-ID: <564a2ac1-9833-9073-b217-85efbdfc2dfb@linux.alibaba.com>
Date:   Thu, 15 Sep 2022 10:08:37 +0800
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Subject: Re: [PATCH] mm,hwpoison: check mm when killing accessing process
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To:     Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc:     linmiaohe@huawei.com, akpm@linux-foundation.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        cuibixuan@linux.alibaba.com, baolin.wang@linux.alibaba.com,
        zhuo.song@linux.alibaba.com,
        Naoya Horiguchi <naoya.horiguchi@nec.com>
References: <20220915012626.GA1791458@hori.linux.bs1.fc.nec.co.jp>
From:   Shuai Xue <xueshuai@linux.alibaba.com>
In-Reply-To: <20220915012626.GA1791458@hori.linux.bs1.fc.nec.co.jp>
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在 2022/9/15 AM9:48, Naoya Horiguchi 写道:
> On Wed, Sep 14, 2022 at 02:49:35PM +0800, Shuai Xue wrote:
>> The GHES code calls memory_failure_queue() from IRQ context to queue work
>> into workqueue and schedule it on the current CPU. Then the work is
>> processed in memory_failure_work_func() by kworker and calls
>> memory_failure().
>>
>> When a page is already poisoned, commit a3f5d80ea401 ("mm,hwpoison: send
>> SIGBUS with error virutal address") make memory_failure() call
>> kill_accessing_process() that:
>>
>>     - holds mmap locking of current->mm
>>     - does pagetable walk to find the error virtual address
>>     - and sends SIGBUS to the current process with error info.
>>
>> However, the mm of kworker is not valid. Therefore, check mm when killing
>> accessing process.
>>
>> Fixes: a3f5d80ea401 ("mm,hwpoison: send SIGBUS with error virutal address")
>> Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
> 
> Thank you for the patch, the fix itself makes sense to me.
> I agree with this patch with applying comments from Andrew.
> 
> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>

Thank you for prompt review.

Cheers,
Shuai