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Subject: Re: [PATCH] xen: xenbus: Fix a possible data race in xs_request_enter
To:     Juergen Gross <jgross@suse.com>, boris.ostrovsky@oracle.com,
        simon@invisiblethingslab.com, joao.m.martins@oracle.com
Cc:     xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
References: <20180508033429.12749-1-baijiaju1990@gmail.com>
 <ea5634a2-b0e2-0fac-e5ec-cef1083958fe@suse.com>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <770bc26b-3819-2235-132f-55b0319955dd@gmail.com>
Date:   Tue, 8 May 2018 15:04:13 +0800
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On 2018/5/8 15:02, Juergen Gross wrote:
> On 08/05/18 05:34, Jia-Ju Bai wrote:
>> The read operation to "req->type" is protected by
>> the lock on line 128, but the write operation to
>> this data on line 118 is not protected by the lock.
>> Thus, there may exist a data race for "req->type".
>>
>> To fix this data race, the write operation to "req->type"
>> should be also protected by the lock.
> No, xs_request_enter() is never called for a request already visible to
> another thread or processor. So no race exists.

Okay, thanks for your reply.


Best wishes,
Jia-Ju Bai