linux-kernel - Re: [PATCH v2] mm: fix unexpected changes to {failslab|fail_page

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Message-ID: <039ce475-f935-e0c2-4734-1dd57519d961@bytedance.com>
Date:   Mon, 14 Nov 2022 11:59:47 +0800
From:   Qi Zheng <zhengqi.arch@...edance.com>
To:     Akinobu Mita <akinobu.mita@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     dvyukov@...gle.com, jgg@...dia.com, willy@...radead.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] mm: fix unexpected changes to
 {failslab|fail_page_alloc}.attr



On 2022/11/9 01:36, Akinobu Mita wrote:
> 2022年11月8日(火) 12:52 Qi Zheng <zhengqi.arch@...edance.com>:
>>
>> When we specify __GFP_NOWARN, we only expect that no warnings
>> will be issued for current caller. But in the __should_failslab()
>> and __should_fail_alloc_page(), the local GFP flags alter the
>> global {failslab|fail_page_alloc}.attr, which is persistent and
>> shared by all tasks. This is not what we expected, let's fix it.
>>
>> Cc: stable@...r.kernel.org
>> Fixes: 3f913fc5f974 ("mm: fix missing handler for __GFP_NOWARN")
>> Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
>> Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
>> ---
>>   v1: https://lore.kernel.org/lkml/20221107033109.59709-1-zhengqi.arch@bytedance.com/
>>
>>   Changelog in v1 -> v2:
>>    - add comment for __should_failslab() and __should_fail_alloc_page()
>>      (suggested by Jason)
> 
> Looks good.
> 
> Reviewed-by: Akinobu Mita <akinobu.mita@...il.com>

Thanks. And hi Andrew, seems no action left for me, can this patch
be applied to mm-unstable tree for testing? :)

-- 
Thanks,
Qi