linux-kernel - Re: [PATCH] mm/hugetlb: Don't put_page in lock of hugetlb

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Message-ID: <d82df01c-09e8-4e3d-4e01-d4df87936f75@huawei.com>
Date:   Mon, 6 May 2019 22:05:45 +0800
From:   Zhiqiang Liu <liuzhiqiang26@...wei.com>
To:     Michal Hocko <mhocko@...nel.org>
CC:     <mike.kravetz@...cle.com>, <shenkai8@...wei.com>,
        <linfeilong@...wei.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <wangwang2@...wei.com>,
        "Zhoukang (A)" <zhoukang7@...wei.com>,
        Mingfangsen <mingfangsen@...wei.com>, <agl@...ibm.com>,
        <nacc@...ibm.com>
Subject: Re: [PATCH] mm/hugetlb: Don't put_page in lock of hugetlb_lock

> On Sat 04-05-19 20:28:24, Zhiqiang Liu wrote:
>> From: Kai Shen <shenkai8@...wei.com>
>>
>> spinlock recursion happened when do LTP test:
>> #!/bin/bash
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>>

>> Fixes: 9980d744a0 ("mm, hugetlb: get rid of surplus page accounting tricks")
>> Signed-off-by: Kai Shen <shenkai8@...wei.com>
>> Signed-off-by: Feilong Lin <linfeilong@...wei.com>
>> Reported-by: Wang Wang <wangwang2@...wei.com>
> 
> You are right. I must have completely missed that put_page path
> unconditionally takes the hugetlb_lock for hugetlb pages.
> 
> Thanks for fixing this. I think this should be marked for stable
> because it is not hard to imagine a regular user might trigger this.
> 
> Acked-by: Michal Hocko <mhocko@...e.com>

Thank you for your reply.
I will add Acked-by: Michal Hocko <mhocko@...e.com> in the v2 patch.