Re: [PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-05-30 Thread Alexandre Courbot
On Tue, May 30, 2017 at 5:30 PM, Sylwester Nawrocki
 wrote:
> Hi,
>
> On 05/29/2017 09:08 PM, Jacek Anaszewski wrote:
>>
>> This patch seems to have lost somehow. Could you help merging it?
>
>
> It's not lost, it has been on my todo queue. I have applied it now.

Awesome, thanks!


Re: [PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-05-30 Thread Sylwester Nawrocki

Hi,

On 05/29/2017 09:08 PM, Jacek Anaszewski wrote:

This patch seems to have lost somehow. Could you help merging it?


It's not lost, it has been on my todo queue. I have applied it now.

--
Thanks,
Sylwester


Re: [PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-05-29 Thread Jacek Anaszewski
Hi Mauro,

This patch seems to have lost somehow. Could you help merging it?

Thanks,
Jacek Anaszewski

On 05/29/2017 09:29 AM, Alexandre Courbot wrote:
> Hi everyone,
> 
> On Thu, Apr 27, 2017 at 4:35 AM, Jacek Anaszewski
>  wrote:
>> On 04/26/2017 04:54 AM, Alexandre Courbot wrote:
>>> On Wed, Apr 26, 2017 at 4:15 AM, Jacek Anaszewski
>>>  wrote:
 Hi Alexandre,

 Thanks for the patch.

 On 04/25/2017 08:19 AM, Alexandre Courbot wrote:
> v4l2_m2m_job_finish(), which is called from the interrupt handler withHi s
> slock acquired, can call the device_run() hook immediately if another
> context was in the queue. This hook also acquires slock, resulting in
> a deadlock for this scenario.
>
> Fix this by releasing slock right before calling v4l2_m2m_job_finish().
> This is safe to do as the state of the hardware cannot change before
> v4l2_m2m_job_finish() is called anyway.
>
> Signed-off-by: Alexandre Courbot 
> ---
>  drivers/media/platform/s5p-jpeg/jpeg-core.c | 12 +---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/platform/s5p-jpeg/jpeg-core.c 
> b/drivers/media/platform/s5p-jpeg/jpeg-core.c
> index 52dc7941db65..223b4379929e 100644
> --- a/drivers/media/platform/s5p-jpeg/jpeg-core.c
> +++ b/drivers/media/platform/s5p-jpeg/jpeg-core.c
> @@ -2642,13 +2642,13 @@ static irqreturn_t s5p_jpeg_irq(int irq, void 
> *dev_id)
>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>   v4l2_m2m_buf_done(dst_buf, state);
> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>
>   curr_ctx->subsampling = s5p_jpeg_get_subsampling_mode(jpeg->regs);
>   spin_unlock(&jpeg->slock);
>
>   s5p_jpeg_clear_int(jpeg->regs);
>
> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>   return IRQ_HANDLED;
>  }
>
> @@ -2707,11 +2707,12 @@ static irqreturn_t exynos4_jpeg_irq(int irq, void 
> *priv)
>   v4l2_m2m_buf_done(dst_vb, VB2_BUF_STATE_ERROR);
>   }
>
> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>   if (jpeg->variant->version == SJPEG_EXYNOS4)
>   curr_ctx->subsampling = 
> exynos4_jpeg_get_frame_fmt(jpeg->regs);
>
>   spin_unlock(&jpeg->slock);
> +
> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>   return IRQ_HANDLED;
>  }
>
> @@ -2770,10 +2771,15 @@ static irqreturn_t exynos3250_jpeg_irq(int irq, 
> void *dev_id)
>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>   v4l2_m2m_buf_done(dst_buf, state);
> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>
>   curr_ctx->subsampling =
>   exynos3250_jpeg_get_subsampling_mode(jpeg->regs);
> +
> + spin_unlock(&jpeg->slock);
> +
> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
> + return IRQ_HANDLED;
> +
>  exit_unlock:
>   spin_unlock(&jpeg->slock);
>   return IRQ_HANDLED;
>

 Acked-by: Jacek Anaszewski 

 Just out of curiosity - could you share how you discovered the problem -
 by some static checkers or trying to use the driver?
>>>
>>> We discovered this issue after adding a new unit test for the jpeg
>>> codec in Chromium OS:
>>>
>>> https://bugs.chromium.org/p/chromium/issues/detail?id=705971
>>>
>>> >From what I understand the test spawns different processes that access
>>> the codec device concurrently, creating the situation leading to the
>>> bug.
>>
>> Thanks for the explanation. Nice fix.
> 
> Gentle ping as I am not seeing this patch in the tree yet. Thanks.
> 
>>
>>> On a slightly related note, I was thinking whether it would make sense
>>> to move the call to  v4l2_m2m_job_finish() (and maybe other parts of
>>> the current interrupt handler) into a worker or a threaded interrupt
>>> handler so as to reduce the time we spend with interrupts disabled.
>>> Can I have your input on this idea?
>>
>> Right, all remaining drivers call it from workers.
>> Feel free to submit a patch.
>>
>> --
>> Best regards,
>> Jacek Anaszewski
> 


Re: [PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-05-29 Thread Alexandre Courbot
Hi everyone,

On Thu, Apr 27, 2017 at 4:35 AM, Jacek Anaszewski
 wrote:
> On 04/26/2017 04:54 AM, Alexandre Courbot wrote:
>> On Wed, Apr 26, 2017 at 4:15 AM, Jacek Anaszewski
>>  wrote:
>>> Hi Alexandre,
>>>
>>> Thanks for the patch.
>>>
>>> On 04/25/2017 08:19 AM, Alexandre Courbot wrote:
 v4l2_m2m_job_finish(), which is called from the interrupt handler with
 slock acquired, can call the device_run() hook immediately if another
 context was in the queue. This hook also acquires slock, resulting in
 a deadlock for this scenario.

 Fix this by releasing slock right before calling v4l2_m2m_job_finish().
 This is safe to do as the state of the hardware cannot change before
 v4l2_m2m_job_finish() is called anyway.

 Signed-off-by: Alexandre Courbot 
 ---
  drivers/media/platform/s5p-jpeg/jpeg-core.c | 12 +---
  1 file changed, 9 insertions(+), 3 deletions(-)

 diff --git a/drivers/media/platform/s5p-jpeg/jpeg-core.c 
 b/drivers/media/platform/s5p-jpeg/jpeg-core.c
 index 52dc7941db65..223b4379929e 100644
 --- a/drivers/media/platform/s5p-jpeg/jpeg-core.c
 +++ b/drivers/media/platform/s5p-jpeg/jpeg-core.c
 @@ -2642,13 +2642,13 @@ static irqreturn_t s5p_jpeg_irq(int irq, void 
 *dev_id)
   if (curr_ctx->mode == S5P_JPEG_ENCODE)
   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
   v4l2_m2m_buf_done(dst_buf, state);
 - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);

   curr_ctx->subsampling = s5p_jpeg_get_subsampling_mode(jpeg->regs);
   spin_unlock(&jpeg->slock);

   s5p_jpeg_clear_int(jpeg->regs);

 + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
   return IRQ_HANDLED;
  }

 @@ -2707,11 +2707,12 @@ static irqreturn_t exynos4_jpeg_irq(int irq, void 
 *priv)
   v4l2_m2m_buf_done(dst_vb, VB2_BUF_STATE_ERROR);
   }

 - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
   if (jpeg->variant->version == SJPEG_EXYNOS4)
   curr_ctx->subsampling = 
 exynos4_jpeg_get_frame_fmt(jpeg->regs);

   spin_unlock(&jpeg->slock);
 +
 + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
   return IRQ_HANDLED;
  }

 @@ -2770,10 +2771,15 @@ static irqreturn_t exynos3250_jpeg_irq(int irq, 
 void *dev_id)
   if (curr_ctx->mode == S5P_JPEG_ENCODE)
   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
   v4l2_m2m_buf_done(dst_buf, state);
 - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);

   curr_ctx->subsampling =
   exynos3250_jpeg_get_subsampling_mode(jpeg->regs);
 +
 + spin_unlock(&jpeg->slock);
 +
 + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
 + return IRQ_HANDLED;
 +
  exit_unlock:
   spin_unlock(&jpeg->slock);
   return IRQ_HANDLED;

>>>
>>> Acked-by: Jacek Anaszewski 
>>>
>>> Just out of curiosity - could you share how you discovered the problem -
>>> by some static checkers or trying to use the driver?
>>
>> We discovered this issue after adding a new unit test for the jpeg
>> codec in Chromium OS:
>>
>> https://bugs.chromium.org/p/chromium/issues/detail?id=705971
>>
>>>From what I understand the test spawns different processes that access
>> the codec device concurrently, creating the situation leading to the
>> bug.
>
> Thanks for the explanation. Nice fix.

Gentle ping as I am not seeing this patch in the tree yet. Thanks.

>
>> On a slightly related note, I was thinking whether it would make sense
>> to move the call to  v4l2_m2m_job_finish() (and maybe other parts of
>> the current interrupt handler) into a worker or a threaded interrupt
>> handler so as to reduce the time we spend with interrupts disabled.
>> Can I have your input on this idea?
>
> Right, all remaining drivers call it from workers.
> Feel free to submit a patch.
>
> --
> Best regards,
> Jacek Anaszewski


Re: [PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-04-26 Thread Jacek Anaszewski
On 04/26/2017 04:54 AM, Alexandre Courbot wrote:
> On Wed, Apr 26, 2017 at 4:15 AM, Jacek Anaszewski
>  wrote:
>> Hi Alexandre,
>>
>> Thanks for the patch.
>>
>> On 04/25/2017 08:19 AM, Alexandre Courbot wrote:
>>> v4l2_m2m_job_finish(), which is called from the interrupt handler with
>>> slock acquired, can call the device_run() hook immediately if another
>>> context was in the queue. This hook also acquires slock, resulting in
>>> a deadlock for this scenario.
>>>
>>> Fix this by releasing slock right before calling v4l2_m2m_job_finish().
>>> This is safe to do as the state of the hardware cannot change before
>>> v4l2_m2m_job_finish() is called anyway.
>>>
>>> Signed-off-by: Alexandre Courbot 
>>> ---
>>>  drivers/media/platform/s5p-jpeg/jpeg-core.c | 12 +---
>>>  1 file changed, 9 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/media/platform/s5p-jpeg/jpeg-core.c 
>>> b/drivers/media/platform/s5p-jpeg/jpeg-core.c
>>> index 52dc7941db65..223b4379929e 100644
>>> --- a/drivers/media/platform/s5p-jpeg/jpeg-core.c
>>> +++ b/drivers/media/platform/s5p-jpeg/jpeg-core.c
>>> @@ -2642,13 +2642,13 @@ static irqreturn_t s5p_jpeg_irq(int irq, void 
>>> *dev_id)
>>>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>>>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>>>   v4l2_m2m_buf_done(dst_buf, state);
>>> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>>
>>>   curr_ctx->subsampling = s5p_jpeg_get_subsampling_mode(jpeg->regs);
>>>   spin_unlock(&jpeg->slock);
>>>
>>>   s5p_jpeg_clear_int(jpeg->regs);
>>>
>>> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>>   return IRQ_HANDLED;
>>>  }
>>>
>>> @@ -2707,11 +2707,12 @@ static irqreturn_t exynos4_jpeg_irq(int irq, void 
>>> *priv)
>>>   v4l2_m2m_buf_done(dst_vb, VB2_BUF_STATE_ERROR);
>>>   }
>>>
>>> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>>   if (jpeg->variant->version == SJPEG_EXYNOS4)
>>>   curr_ctx->subsampling = 
>>> exynos4_jpeg_get_frame_fmt(jpeg->regs);
>>>
>>>   spin_unlock(&jpeg->slock);
>>> +
>>> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>>   return IRQ_HANDLED;
>>>  }
>>>
>>> @@ -2770,10 +2771,15 @@ static irqreturn_t exynos3250_jpeg_irq(int irq, 
>>> void *dev_id)
>>>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>>>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>>>   v4l2_m2m_buf_done(dst_buf, state);
>>> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>>
>>>   curr_ctx->subsampling =
>>>   exynos3250_jpeg_get_subsampling_mode(jpeg->regs);
>>> +
>>> + spin_unlock(&jpeg->slock);
>>> +
>>> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>> + return IRQ_HANDLED;
>>> +
>>>  exit_unlock:
>>>   spin_unlock(&jpeg->slock);
>>>   return IRQ_HANDLED;
>>>
>>
>> Acked-by: Jacek Anaszewski 
>>
>> Just out of curiosity - could you share how you discovered the problem -
>> by some static checkers or trying to use the driver?
> 
> We discovered this issue after adding a new unit test for the jpeg
> codec in Chromium OS:
> 
> https://bugs.chromium.org/p/chromium/issues/detail?id=705971
> 
>>From what I understand the test spawns different processes that access
> the codec device concurrently, creating the situation leading to the
> bug.

Thanks for the explanation. Nice fix.

> On a slightly related note, I was thinking whether it would make sense
> to move the call to  v4l2_m2m_job_finish() (and maybe other parts of
> the current interrupt handler) into a worker or a threaded interrupt
> handler so as to reduce the time we spend with interrupts disabled.
> Can I have your input on this idea?

Right, all remaining drivers call it from workers.
Feel free to submit a patch.

-- 
Best regards,
Jacek Anaszewski


Re: [PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-04-25 Thread Alexandre Courbot
On Wed, Apr 26, 2017 at 4:15 AM, Jacek Anaszewski
 wrote:
> Hi Alexandre,
>
> Thanks for the patch.
>
> On 04/25/2017 08:19 AM, Alexandre Courbot wrote:
>> v4l2_m2m_job_finish(), which is called from the interrupt handler with
>> slock acquired, can call the device_run() hook immediately if another
>> context was in the queue. This hook also acquires slock, resulting in
>> a deadlock for this scenario.
>>
>> Fix this by releasing slock right before calling v4l2_m2m_job_finish().
>> This is safe to do as the state of the hardware cannot change before
>> v4l2_m2m_job_finish() is called anyway.
>>
>> Signed-off-by: Alexandre Courbot 
>> ---
>>  drivers/media/platform/s5p-jpeg/jpeg-core.c | 12 +---
>>  1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/platform/s5p-jpeg/jpeg-core.c 
>> b/drivers/media/platform/s5p-jpeg/jpeg-core.c
>> index 52dc7941db65..223b4379929e 100644
>> --- a/drivers/media/platform/s5p-jpeg/jpeg-core.c
>> +++ b/drivers/media/platform/s5p-jpeg/jpeg-core.c
>> @@ -2642,13 +2642,13 @@ static irqreturn_t s5p_jpeg_irq(int irq, void 
>> *dev_id)
>>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>>   v4l2_m2m_buf_done(dst_buf, state);
>> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>
>>   curr_ctx->subsampling = s5p_jpeg_get_subsampling_mode(jpeg->regs);
>>   spin_unlock(&jpeg->slock);
>>
>>   s5p_jpeg_clear_int(jpeg->regs);
>>
>> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>   return IRQ_HANDLED;
>>  }
>>
>> @@ -2707,11 +2707,12 @@ static irqreturn_t exynos4_jpeg_irq(int irq, void 
>> *priv)
>>   v4l2_m2m_buf_done(dst_vb, VB2_BUF_STATE_ERROR);
>>   }
>>
>> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>   if (jpeg->variant->version == SJPEG_EXYNOS4)
>>   curr_ctx->subsampling = exynos4_jpeg_get_frame_fmt(jpeg->regs);
>>
>>   spin_unlock(&jpeg->slock);
>> +
>> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>   return IRQ_HANDLED;
>>  }
>>
>> @@ -2770,10 +2771,15 @@ static irqreturn_t exynos3250_jpeg_irq(int irq, void 
>> *dev_id)
>>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>>   v4l2_m2m_buf_done(dst_buf, state);
>> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>>
>>   curr_ctx->subsampling =
>>   exynos3250_jpeg_get_subsampling_mode(jpeg->regs);
>> +
>> + spin_unlock(&jpeg->slock);
>> +
>> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>> + return IRQ_HANDLED;
>> +
>>  exit_unlock:
>>   spin_unlock(&jpeg->slock);
>>   return IRQ_HANDLED;
>>
>
> Acked-by: Jacek Anaszewski 
>
> Just out of curiosity - could you share how you discovered the problem -
> by some static checkers or trying to use the driver?

We discovered this issue after adding a new unit test for the jpeg
codec in Chromium OS:

https://bugs.chromium.org/p/chromium/issues/detail?id=705971

>From what I understand the test spawns different processes that access
the codec device concurrently, creating the situation leading to the
bug.

On a slightly related note, I was thinking whether it would make sense
to move the call to  v4l2_m2m_job_finish() (and maybe other parts of
the current interrupt handler) into a worker or a threaded interrupt
handler so as to reduce the time we spend with interrupts disabled.
Can I have your input on this idea?


Re: [PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-04-25 Thread Jacek Anaszewski
Hi Alexandre,

Thanks for the patch.

On 04/25/2017 08:19 AM, Alexandre Courbot wrote:
> v4l2_m2m_job_finish(), which is called from the interrupt handler with
> slock acquired, can call the device_run() hook immediately if another
> context was in the queue. This hook also acquires slock, resulting in
> a deadlock for this scenario.
> 
> Fix this by releasing slock right before calling v4l2_m2m_job_finish().
> This is safe to do as the state of the hardware cannot change before
> v4l2_m2m_job_finish() is called anyway.
> 
> Signed-off-by: Alexandre Courbot 
> ---
>  drivers/media/platform/s5p-jpeg/jpeg-core.c | 12 +---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/platform/s5p-jpeg/jpeg-core.c 
> b/drivers/media/platform/s5p-jpeg/jpeg-core.c
> index 52dc7941db65..223b4379929e 100644
> --- a/drivers/media/platform/s5p-jpeg/jpeg-core.c
> +++ b/drivers/media/platform/s5p-jpeg/jpeg-core.c
> @@ -2642,13 +2642,13 @@ static irqreturn_t s5p_jpeg_irq(int irq, void *dev_id)
>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>   v4l2_m2m_buf_done(dst_buf, state);
> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>  
>   curr_ctx->subsampling = s5p_jpeg_get_subsampling_mode(jpeg->regs);
>   spin_unlock(&jpeg->slock);
>  
>   s5p_jpeg_clear_int(jpeg->regs);
>  
> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>   return IRQ_HANDLED;
>  }
>  
> @@ -2707,11 +2707,12 @@ static irqreturn_t exynos4_jpeg_irq(int irq, void 
> *priv)
>   v4l2_m2m_buf_done(dst_vb, VB2_BUF_STATE_ERROR);
>   }
>  
> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>   if (jpeg->variant->version == SJPEG_EXYNOS4)
>   curr_ctx->subsampling = exynos4_jpeg_get_frame_fmt(jpeg->regs);
>  
>   spin_unlock(&jpeg->slock);
> +
> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>   return IRQ_HANDLED;
>  }
>  
> @@ -2770,10 +2771,15 @@ static irqreturn_t exynos3250_jpeg_irq(int irq, void 
> *dev_id)
>   if (curr_ctx->mode == S5P_JPEG_ENCODE)
>   vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
>   v4l2_m2m_buf_done(dst_buf, state);
> - v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
>  
>   curr_ctx->subsampling =
>   exynos3250_jpeg_get_subsampling_mode(jpeg->regs);
> +
> + spin_unlock(&jpeg->slock);
> +
> + v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
> + return IRQ_HANDLED;
> +
>  exit_unlock:
>   spin_unlock(&jpeg->slock);
>   return IRQ_HANDLED;
> 

Acked-by: Jacek Anaszewski 

Just out of curiosity - could you share how you discovered the problem -
by some static checkers or trying to use the driver?

-- 
Best regards,
Jacek Anaszewski


[PATCH] [media] s5p-jpeg: fix recursive spinlock acquisition

2017-04-24 Thread Alexandre Courbot
v4l2_m2m_job_finish(), which is called from the interrupt handler with
slock acquired, can call the device_run() hook immediately if another
context was in the queue. This hook also acquires slock, resulting in
a deadlock for this scenario.

Fix this by releasing slock right before calling v4l2_m2m_job_finish().
This is safe to do as the state of the hardware cannot change before
v4l2_m2m_job_finish() is called anyway.

Signed-off-by: Alexandre Courbot 
---
 drivers/media/platform/s5p-jpeg/jpeg-core.c | 12 +---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/s5p-jpeg/jpeg-core.c 
b/drivers/media/platform/s5p-jpeg/jpeg-core.c
index 52dc7941db65..223b4379929e 100644
--- a/drivers/media/platform/s5p-jpeg/jpeg-core.c
+++ b/drivers/media/platform/s5p-jpeg/jpeg-core.c
@@ -2642,13 +2642,13 @@ static irqreturn_t s5p_jpeg_irq(int irq, void *dev_id)
if (curr_ctx->mode == S5P_JPEG_ENCODE)
vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
v4l2_m2m_buf_done(dst_buf, state);
-   v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
 
curr_ctx->subsampling = s5p_jpeg_get_subsampling_mode(jpeg->regs);
spin_unlock(&jpeg->slock);
 
s5p_jpeg_clear_int(jpeg->regs);
 
+   v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
return IRQ_HANDLED;
 }
 
@@ -2707,11 +2707,12 @@ static irqreturn_t exynos4_jpeg_irq(int irq, void *priv)
v4l2_m2m_buf_done(dst_vb, VB2_BUF_STATE_ERROR);
}
 
-   v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
if (jpeg->variant->version == SJPEG_EXYNOS4)
curr_ctx->subsampling = exynos4_jpeg_get_frame_fmt(jpeg->regs);
 
spin_unlock(&jpeg->slock);
+
+   v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
return IRQ_HANDLED;
 }
 
@@ -2770,10 +2771,15 @@ static irqreturn_t exynos3250_jpeg_irq(int irq, void 
*dev_id)
if (curr_ctx->mode == S5P_JPEG_ENCODE)
vb2_set_plane_payload(&dst_buf->vb2_buf, 0, payload_size);
v4l2_m2m_buf_done(dst_buf, state);
-   v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
 
curr_ctx->subsampling =
exynos3250_jpeg_get_subsampling_mode(jpeg->regs);
+
+   spin_unlock(&jpeg->slock);
+
+   v4l2_m2m_job_finish(jpeg->m2m_dev, curr_ctx->fh.m2m_ctx);
+   return IRQ_HANDLED;
+
 exit_unlock:
spin_unlock(&jpeg->slock);
return IRQ_HANDLED;
-- 
2.13.0.rc0.306.g87b477812d-goog