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Subject: Re: [PATCH] acpi: scan: Fix a possible data race in
 acpi_scan_hotplug_enabled
To:     "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <20180508030811.12256-1-baijiaju1990@gmail.com>
 <CAJZ5v0jqW0yuSOSrgy1=dWARPHmaxtG4fvkZj=pX+fPcTTJh1A@mail.gmail.com>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <1b7f1bff-b38b-fe10-3e1c-2b465b36f193@gmail.com>
Date:   Wed, 9 May 2018 11:17:38 +0800
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On 2018/5/9 4:17, Rafael J. Wysocki wrote:
> On Tue, May 8, 2018 at 5:08 AM, Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
>> The write operation to "hotplug->enabled" is protected by
>> the lock on line 1760, but the read operation to
>> this data on line 1755 is not protected by the lock.
>> Thus, there may exist a data race for "hotplug->enabled".
> Either it does exist, or it doesn't.
>
> If it exists, it needs to be fixed.  If it doesn't exist, nothing
> needs to be done.
>
> Which is the case?

I only read the code and find this possible data race.
It is not found in real driver execution.
I am not sure of it, so I use "may" and "possible" here.


Best wishes,
Jia-Ju Bai