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Subject: Re: [PATCH] mm,hwpoison: unmap poisoned page before invalidation
To:     Rik van Riel <riel@surriel.com>
CC:     <linux-mm@kvack.org>, <kernel-team@fb.com>,
        Oscar Salvador <osalvador@suse.de>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        Mel Gorman <mgorman@suse.de>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        <stable@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <acc49e6b-acb4-2001-3bdd-241160811020@huawei.com>
Date:   Mon, 28 Mar 2022 10:41:49 +0800
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On 2022/3/28 10:24, Rik van Riel wrote:
> On Mon, 2022-03-28 at 10:14 +0800, Miaohe Lin wrote:
>> On 2022/3/27 4:14, Rik van Riel wrote:
>>
>>
>>>
>>>>>                         /* Retry if a clean page was removed
>>>>> from
>>>>> the cache. */
>>>>> -                       if (invalidate_inode_page(vmf->page))
>>>>> -                               poisonret = 0;
>>>>> -                       unlock_page(vmf->page);
>>>>> +                       if (invalidate_inode_page(page))
>>>>> +                               poisonret = VM_FAULT_NOPAGE;
>>>>> +                       unlock_page(page);
>>>
>>
>> Sure, but when I think more about this, it seems this fix isn't
>> ideal:
>> If VM_FAULT_NOPAGE is returned with page table unset, the process
>> will
>> re-trigger page fault again and again until invalidate_inode_page
>> succeeds
>> to evict the inode page. This might hang the process a really long
>> time.
>> Or am I miss something?
>>
> If invalidate_inode_page fails, we will return
> VM_FAULT_HWPOISON, and kill the task, instead
> of looping indefinitely.

Oh, really sorry! It's a drowsy Monday morning. :)

This patch looks good to me. Thanks!

Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>

>