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Subject: Re: [PATCH v3 1/2] mm/swapfile: fix possible data races of
 inuse_pages
To:     Qian Cai <quic_qiancai@quicinc.com>
CC:     <akpm@linux-foundation.org>, <david@redhat.com>,
        <ying.huang@intel.com>, <songmuchun@bytedance.com>,
        <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
References: <20220625093346.48894-1-linmiaohe@huawei.com>
 <20220625093346.48894-2-linmiaohe@huawei.com> <Yrml4mB3sa5fZVJa@qian>
From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <fe3c4834-71a6-7867-2108-eca43fde62fc@huawei.com>
Date:   Mon, 27 Jun 2022 21:27:43 +0800
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On 2022/6/27 20:43, Qian Cai wrote:
> On Sat, Jun 25, 2022 at 05:33:45PM +0800, Miaohe Lin wrote:
>> si->inuse_pages could still be accessed concurrently now. The plain reads
>> outside si->lock critical section, i.e. swap_show and si_swapinfo, which
>> results in data races. READ_ONCE and WRITE_ONCE is used to fix such data
>> races. Note these data races should be ok because they're just used for
>> showing swap info.
> 
> Was this found by kcsan? If so, it would be useful to record the exact
> kscan report in the commit message.

Sorry, it's found via code inspection.

Thanks.

> .
>