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Subject: Re: [PATCH AUTOSEL 4.9 20/57] media: sta2x11: Add video_device and
 vb2_queue locks
From:   Ezequiel Garcia <ezequiel@collabora.com>
To:     Sasha Levin <Alexander.Levin@microsoft.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc:     Hans Verkuil <hans.verkuil@cisco.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Date:   Mon, 17 Sep 2018 08:50:27 -0300
In-Reply-To: <20180917030340.378-20-alexander.levin@microsoft.com>
References: <20180917030340.378-1-alexander.levin@microsoft.com>
         <20180917030340.378-20-alexander.levin@microsoft.com>
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Hi Sasha,

On Mon, 2018-09-17 at 03:03 +0000, Sasha Levin wrote:
> From: Ezequiel Garcia <ezequiel@collabora.com>
> 
> [ Upstream commit cd63c0288fd760ce7de247fba618e2bbcfc0c35c ]
> 
> Currently, this driver does not serialize its video4linux
> ioctls, which is a bug, as race conditions might appear.
> 
> In addition, video_device and vb2_queue locks are now both
> mandatory. Add them, and implement wait_prepare and
> wait_finish.
> 
> To stay on the safe side, this commit uses a single mutex
> for both locks. Better latency can be obtained by separating
> these if needed.
> 
> Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>

Hm, I am not so sure this patch should go to -stable,
as it's not fixing a real bug we've seen out there.

Regards,
Eze