linux-kernel - Re: [PATCH] mm/hugetlb: avoid get wrong ptep caused by race

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Message-ID: <593d82a3-1d1e-d8f2-6b90-137f10441522@huawei.com>
Date:   Wed, 19 Feb 2020 10:09:46 +0800
From:   "Longpeng (Mike)" <longpeng2@...wei.com>
To:     Matthew Wilcox <willy@...radead.org>
CC:     <mike.kravetz@...cle.com>, <akpm@...ux-foundation.org>,
        <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <arei.gonglei@...wei.com>, <weidong.huang@...wei.com>,
        <weifuqiang@...wei.com>, <kvm@...r.kernel.org>
Subject: Re: [PATCH] mm/hugetlb: avoid get wrong ptep caused by race

在 2020/2/19 4:52, Matthew Wilcox 写道:
> On Tue, Feb 18, 2020 at 08:10:25PM +0800, Longpeng(Mike) wrote:
>>  {
>> -	pgd_t *pgd;
>> -	p4d_t *p4d;
>> -	pud_t *pud;
>> -	pmd_t *pmd;
>> +	pgd_t *pgdp;
>> +	p4d_t *p4dp;
>> +	pud_t *pudp, pud;
>> +	pmd_t *pmdp, pmd;
> 
> Renaming the variables as part of a fix is a really bad idea.  It obscures
> the actual fix and makes everybody's life harder.  Plus, it's not even
> renaming to follow the normal convention -- there are only two places
> (migrate.c and gup.c) which follow this pattern in mm/ while there are
> 33 that do not.
> 
Good suggestion, I've never noticed this, thanks.
By the way, could you give an example if we use this way to fix the bug?

> 
> .
> 


-- 
Regards,
Longpeng(Mike)