linux-kernel - Re: [PATCH] mm,hwpoison: check mm when killing accessing process

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Date:   Thu, 15 Sep 2022 10:08:37 +0800
From:   Shuai Xue <xueshuai@...ux.alibaba.com>
To:     Naoya Horiguchi <naoya.horiguchi@...ux.dev>
Cc:     linmiaohe@...wei.com, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        cuibixuan@...ux.alibaba.com, baolin.wang@...ux.alibaba.com,
        zhuo.song@...ux.alibaba.com,
        Naoya Horiguchi <naoya.horiguchi@....com>
Subject: Re: [PATCH] mm,hwpoison: check mm when killing accessing process



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@...ux.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@....com>

Thank you for prompt review.

Cheers,
Shuai