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Subject: Re: [PATCH] watchdog: mena21_wdt: Fix a possible data race in
 a21_wdt_set_timeout
To:     Guenter Roeck <linux@roeck-us.net>, morbidrsa@gmail.com,
        wim@linux-watchdog.org
Cc:     linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20180508031825.12525-1-baijiaju1990@gmail.com>
 <64e08944-0578-ac4c-8dea-e1e704685e77@roeck-us.net>
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Message-ID: <26fde8a3-fb78-e12f-2f0f-c9b5bb2158e0@gmail.com>
Date:   Tue, 8 May 2018 11:32:20 +0800
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On 2018/5/8 11:28, Guenter Roeck wrote:
> On 05/07/2018 08:18 PM, Jia-Ju Bai wrote:
>> The write operation to "wdt->timeout" is protected by
>> the lock on line 118, but the read operation to
>> this data on line 105 is not protected by the lock.
>> Thus, there may exist a data race for "wdt->timeout".
>>
>> To fix this data race, the read operation to "wdt->timeout"
>> should be also protected by the lock.
>>
>
> There is no race. There is already a mutex in the watchdog core which 
> serializes
> calls to the various API functions. It would make more sense to drop 
> drv->lock
> from the driver.
>

Thanks for your reply :)
Need I submit a patch of dropping all calls to "drv->lock"?


Best wishes,
Jia-Ju Bai