linux-kernel - Re: [PATCH 3/3] mm/memory-failure: send SIGBUS in the event of thp split fail

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Date: Thu, 9 May 2024 16:52:17 +0800
From: Miaohe Lin <linmiaohe@...wei.com>
To: Jane Chu <jane.chu@...cle.com>, <nao.horiguchi@...il.com>,
	<akpm@...ux-foundation.org>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] mm/memory-failure: send SIGBUS in the event of thp
 split fail

On 2024/5/9 0:56, Jane Chu wrote:
> On 5/8/2024 2:03 AM, Miaohe Lin wrote:
> 
>> On 2024/5/2 7:24, Jane Chu wrote:
>>> When handle hwpoison in a GUP longterm pin'ed thp page,
>>> try_to_split_thp_page() will fail. And at this point, there is little else
>>> the kernel could do except sending a SIGBUS to the user process, thus
>>> give it a chance to recover.
>> It seems the user process will still receive SIGBUS via kill_accessing_process()
>> when (re-)access thp later. So they should have a chance to recover already.
>> Or am I miss something?
> 
> The concern is about real UE consumption in which case, it's desirable to kill the process ASAP without having to relying on subsequent access.  Also to honor processes' MCE-early-kill request. kill_accessing_process() is very conservative in that, it doesn't check other processes that have the poisoned page mapped.

I see. Thanks for your explanation.
Thanks.
.

> 
> thanks,
> 
> -jane
> 
>>
>> Thanks.
>> .
>>
>>
> .