* au0828_init_tuner() called without dev lock held
@ 2014-09-22 16:31 Shuah Khan
2014-09-22 16:37 ` Hans Verkuil
0 siblings, 1 reply; 3+ messages in thread
From: Shuah Khan @ 2014-09-22 16:31 UTC (permalink / raw)
To: Hans Verkuil, mauro Carvalho Chehab (m.chehab@samsung.com),
Linux Media Mailing List, Shuah Khan
Hi Hans and Mauro,
While I was making changes for media token work, I noticed there are
several places au0828_init_tuner() gets called without holding dev lock.
vidioc_s_std(), vidioc_g_tuner(), vidioc_s_tuner(), vidioc_streamon()
au0828_v4l2_resume()
Some of these might be intended since au0828_init_tuner() invokes
s_std. All of these changes including the au0828_init_tuner() itself
were added in ea86968fb91471493ccac7d8f2a65bc65db6803b
au0828_v4l2_resume() also does this and this one for sure needs fixing
very likely. I am not sure about the others. Thoughts??
-- Shuah
--
Shuah Khan
Sr. Linux Kernel Developer
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: au0828_init_tuner() called without dev lock held
2014-09-22 16:31 au0828_init_tuner() called without dev lock held Shuah Khan
@ 2014-09-22 16:37 ` Hans Verkuil
2014-09-22 16:40 ` Shuah Khan
0 siblings, 1 reply; 3+ messages in thread
From: Hans Verkuil @ 2014-09-22 16:37 UTC (permalink / raw)
To: Shuah Khan, mauro Carvalho Chehab (m.chehab@samsung.com),
Linux Media Mailing List
On 09/22/2014 06:31 PM, Shuah Khan wrote:
> Hi Hans and Mauro,
>
> While I was making changes for media token work, I noticed there are
> several places au0828_init_tuner() gets called without holding dev lock.
au0828 sets the lock pointer in struct video_device to the dev lock.
That means that all v4l2 ioctl calls are serialized in v4l2_ioctl()
in v4l2-dev.c. So these calls *do* hold the device lock.
Not au0828_v4l2_resume() though, that's not an ioctl op.
Regards,
Hans
>
> vidioc_s_std(), vidioc_g_tuner(), vidioc_s_tuner(), vidioc_streamon()
> au0828_v4l2_resume()
>
> Some of these might be intended since au0828_init_tuner() invokes
> s_std. All of these changes including the au0828_init_tuner() itself
> were added in ea86968fb91471493ccac7d8f2a65bc65db6803b
>
> au0828_v4l2_resume() also does this and this one for sure needs fixing
> very likely. I am not sure about the others. Thoughts??
>
> -- Shuah
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: au0828_init_tuner() called without dev lock held
2014-09-22 16:37 ` Hans Verkuil
@ 2014-09-22 16:40 ` Shuah Khan
0 siblings, 0 replies; 3+ messages in thread
From: Shuah Khan @ 2014-09-22 16:40 UTC (permalink / raw)
To: Hans Verkuil, mauro Carvalho Chehab (m.chehab@samsung.com),
Linux Media Mailing List
On 09/22/2014 10:37 AM, Hans Verkuil wrote:
> On 09/22/2014 06:31 PM, Shuah Khan wrote:
>> Hi Hans and Mauro,
>>
>> While I was making changes for media token work, I noticed there are
>> several places au0828_init_tuner() gets called without holding dev lock.
>
> au0828 sets the lock pointer in struct video_device to the dev lock.
> That means that all v4l2 ioctl calls are serialized in v4l2_ioctl()
> in v4l2-dev.c. So these calls *do* hold the device lock.
>
> Not au0828_v4l2_resume() though, that's not an ioctl op.
>
Good. I will go ahead and fix au0828_v4l2_resume() to do
it right.
thanks,
-- Shuah
--
Shuah Khan
Sr. Linux Kernel Developer
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978
^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-09-22 16:31 au0828_init_tuner() called without dev lock held Shuah Khan
2014-09-22 16:37 ` Hans Verkuil
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