RE: [PATCH] media: staging/intel-ipu3: Implement lock for stream on/off operations
Hi Sakari,
[snip]
> > > > > fail_stop_pipeline:
> > > > > @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct
> > > > vb2_queue *vq)
> > > > > dev_err(>pci_dev->dev,
> > > > > "failed to stop subdev streaming\n");
> > > > >
> > > > > + mutex_lock(>streaming_lock);
> > > > > +
> > > > > /* Was this the first node with streaming disabled? */
> > > > > if (imgu->streaming && ipu3_all_nodes_streaming(imgu, node)) {
> > > > > /* Yes, really stop streaming now */ @@ -552,6 +557,7 @@
> > > > static
> > > > > void ipu3_vb2_stop_streaming(struct vb2_queue *vq)
> > > > > imgu->streaming = false;
> > > > > }
> > > > >
> > > > > + mutex_unlock(>streaming_lock);
> > > > > ipu3_return_all_buffers(imgu, node, VB2_BUF_STATE_ERROR);
> >
> > I'd also call ipu3_return_all_buffers() before releasing the lock: in
> > principle the user may have queued new buffers on the devices before
> > the driver marks the buffers as faulty.
> >
Ack
(Somehow I missed this comment.)
[snip]
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RE: [PATCH] media: staging/intel-ipu3: Implement lock for stream on/off operations
Hi Sakari, > Subject: Re: [PATCH] media: staging/intel-ipu3: Implement lock for stream > on/off operations > > Hi Raj, > > On Wed, Jan 30, 2019 at 05:17:15PM +, Mani, Rajmohan wrote: > > Hi Sakari, > > > > > -Original Message- > > > From: Sakari Ailus [mailto:sakari.ai...@linux.intel.com] > > > Sent: Wednesday, January 30, 2019 12:59 AM > > > To: Mani, Rajmohan > > > Cc: Mauro Carvalho Chehab ; Greg Kroah-Hartman > > > ; linux-me...@vger.kernel.org; > > > de...@driverdev.osuosl.org; linux-ker...@vger.kernel.org; Laurent > > > Pinchart ; Jacopo Mondi > > > ; Qiu, Tian Shu ; Cao, > > > Bingbu ; z...@paasikivi.fi.intel.com; Zhi, Yong > > > ; hverk...@xs4all.nl; tf...@chromium.org > > > Subject: Re: [PATCH] media: staging/intel-ipu3: Implement lock for > > > stream on/off operations > > > > > > Hi Rajmohan, > > > > > > On Tue, Jan 29, 2019 at 02:27:36PM -0800, Rajmohan Mani wrote: > > > > Currently concurrent stream off operations on ImgU nodes are not > > > > synchronized, leading to use-after-free bugs (as reported by KASAN). > > > > > > > > [ 250.090724] BUG: KASAN: use-after-free in > > > > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090726] Read of > > > > size 8 at addr 888127b29bc0 by task yavta/18836 [ 250.090731] > > > > Hardware > > > > name: HP Soraka/Soraka, BIOS Google_Soraka.10431.17.0 03/22/2018 [ > > > 250.090732] Call Trace: > > > > [ 250.090735] dump_stack+0x6a/0xb1 [ 250.090739] > > > > print_address_description+0x8e/0x279 > > > > [ 250.090743] ? ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ > > > > 250.090746] kasan_report+0x260/0x28a [ 250.090750] > > > > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090754] > > > > ipu3_css_pool_cleanup+0x24/0x37 [ipu3_imgu] [ 250.090759] > > > > ipu3_css_pipeline_cleanup+0x61/0xb9 [ipu3_imgu] [ 250.090763] > > > > ipu3_css_stop_streaming+0x1f2/0x321 [ipu3_imgu] [ 250.090768] > > > > imgu_s_stream+0x94/0x443 [ipu3_imgu] [ 250.090772] ? > > > > ipu3_vb2_buf_queue+0x280/0x280 [ipu3_imgu] [ 250.090775] ? > > > > vb2_dma_sg_unmap_dmabuf+0x16/0x6f [videobuf2_dma_sg] [ > > > > 250.090778] > > > ? > > > > vb2_buffer_in_use+0x36/0x58 [videobuf2_common] [ 250.090782] > > > > ipu3_vb2_stop_streaming+0xf9/0x135 [ipu3_imgu] > > > > > > > > Implemented a lock to synchronize imgu stream on / off operations > > > > and the modification of streaming flag (in struct imgu_device), to > > > > prevent these issues. > > > > > > > > Reported-by: Laurent Pinchart > > > > Suggested-by: Laurent Pinchart > > > > > > > > Signed-off-by: Rajmohan Mani > > > > --- > > > > drivers/staging/media/ipu3/ipu3-v4l2.c | 6 ++ > > > > drivers/staging/media/ipu3/ipu3.c | 3 +++ > > > > drivers/staging/media/ipu3/ipu3.h | 4 > > > > 3 files changed, 13 insertions(+) > > > > > > > > diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c > > > > b/drivers/staging/media/ipu3/ipu3-v4l2.c > > > > index c7936032beb9..cf7e917cd0c8 100644 > > > > --- a/drivers/staging/media/ipu3/ipu3-v4l2.c > > > > +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c > > > > @@ -507,12 +507,15 @@ static int ipu3_vb2_start_streaming(struct > > > vb2_queue *vq, unsigned int count) > > > > goto fail_stop_pipeline; > > > > } > > > > > > > > + mutex_lock(>streaming_lock); > > > > + > > > > > > You appear to be using imgu_device.lock (while searching buffers to > > > queue to the device) as well as imgu_video_device.lock (qbuf, dqbuf) > > > to serialise access to imgu_video_device.buffers list. > > > > Ack > > > > > The two locks may be acquired at the same time but each by different > > > processes. That needs to be addressed, but probably not in this > > > patch. > > > > > > > The node specific locks will be used by different processes and all of > > these processes will be competing commonly (and successfully) for the > imgu_device lock. > > I will look into this more. > > > > > I wonder if it'd be more simple to use imgu->lock here instead of > > > adding a new one. > > > > > > > Extending img
Re: [PATCH] media: staging/intel-ipu3: Implement lock for stream on/off operations
Hi Raj, On Wed, Jan 30, 2019 at 05:17:15PM +, Mani, Rajmohan wrote: > Hi Sakari, > > > -Original Message- > > From: Sakari Ailus [mailto:sakari.ai...@linux.intel.com] > > Sent: Wednesday, January 30, 2019 12:59 AM > > To: Mani, Rajmohan > > Cc: Mauro Carvalho Chehab ; Greg Kroah-Hartman > > ; linux-me...@vger.kernel.org; > > de...@driverdev.osuosl.org; linux-ker...@vger.kernel.org; Laurent Pinchart > > ; Jacopo Mondi ; > > Qiu, Tian Shu ; Cao, Bingbu > > ; z...@paasikivi.fi.intel.com; Zhi, Yong > > ; hverk...@xs4all.nl; tf...@chromium.org > > Subject: Re: [PATCH] media: staging/intel-ipu3: Implement lock for stream > > on/off operations > > > > Hi Rajmohan, > > > > On Tue, Jan 29, 2019 at 02:27:36PM -0800, Rajmohan Mani wrote: > > > Currently concurrent stream off operations on ImgU nodes are not > > > synchronized, leading to use-after-free bugs (as reported by KASAN). > > > > > > [ 250.090724] BUG: KASAN: use-after-free in > > > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090726] Read of size 8 > > > at addr 888127b29bc0 by task yavta/18836 [ 250.090731] Hardware > > > name: HP Soraka/Soraka, BIOS Google_Soraka.10431.17.0 03/22/2018 [ > > 250.090732] Call Trace: > > > [ 250.090735] dump_stack+0x6a/0xb1 > > > [ 250.090739] print_address_description+0x8e/0x279 > > > [ 250.090743] ? ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ > > > 250.090746] kasan_report+0x260/0x28a [ 250.090750] > > > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090754] > > > ipu3_css_pool_cleanup+0x24/0x37 [ipu3_imgu] [ 250.090759] > > > ipu3_css_pipeline_cleanup+0x61/0xb9 [ipu3_imgu] [ 250.090763] > > > ipu3_css_stop_streaming+0x1f2/0x321 [ipu3_imgu] [ 250.090768] > > > imgu_s_stream+0x94/0x443 [ipu3_imgu] [ 250.090772] ? > > > ipu3_vb2_buf_queue+0x280/0x280 [ipu3_imgu] [ 250.090775] ? > > > vb2_dma_sg_unmap_dmabuf+0x16/0x6f [videobuf2_dma_sg] [ 250.090778] > > ? > > > vb2_buffer_in_use+0x36/0x58 [videobuf2_common] [ 250.090782] > > > ipu3_vb2_stop_streaming+0xf9/0x135 [ipu3_imgu] > > > > > > Implemented a lock to synchronize imgu stream on / off operations and > > > the modification of streaming flag (in struct imgu_device), to prevent > > > these issues. > > > > > > Reported-by: Laurent Pinchart > > > Suggested-by: Laurent Pinchart > > > > > > Signed-off-by: Rajmohan Mani > > > --- > > > drivers/staging/media/ipu3/ipu3-v4l2.c | 6 ++ > > > drivers/staging/media/ipu3/ipu3.c | 3 +++ > > > drivers/staging/media/ipu3/ipu3.h | 4 > > > 3 files changed, 13 insertions(+) > > > > > > diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c > > > b/drivers/staging/media/ipu3/ipu3-v4l2.c > > > index c7936032beb9..cf7e917cd0c8 100644 > > > --- a/drivers/staging/media/ipu3/ipu3-v4l2.c > > > +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c > > > @@ -507,12 +507,15 @@ static int ipu3_vb2_start_streaming(struct > > vb2_queue *vq, unsigned int count) > > > goto fail_stop_pipeline; > > > } > > > > > > + mutex_lock(>streaming_lock); > > > + > > > > You appear to be using imgu_device.lock (while searching buffers to queue to > > the device) as well as imgu_video_device.lock (qbuf, dqbuf) to serialise > > access > > to imgu_video_device.buffers list. > > Ack > > > The two locks may be acquired at the same > > time but each by different processes. That needs to be addressed, but > > probably not in this patch. > > > > The node specific locks will be used by different processes and all of these > processes > will be competing commonly (and successfully) for the imgu_device lock. > I will look into this more. > > > I wonder if it'd be more simple to use imgu->lock here instead of adding a > > new > > one. > > > > Extending imgu->lock here, does not work in this case, as imgu_queue_buffers() > will be stuck acquiring imgu->lock, which was already acquired by > imgu_s_stream() > through ipu3_vb2_start_streaming(). You could move acquiring the lock out of these functions. It would also seem that there is device-wide streaming state etc. information to which the access should also be serialised. Currently it's relying on the node-specific lock only which does not help. Can you grab the lock right after dev_dbg() line in the function? The lock should be also acquired before testing imgu->streaming in
Re: [PATCH] media: staging/intel-ipu3: Implement lock for stream on/off operations
Hi Raj, On Wed, Jan 30, 2019 at 05:17:15PM +, Mani, Rajmohan wrote: > Hi Sakari, > > > -Original Message- > > From: Sakari Ailus [mailto:sakari.ai...@linux.intel.com] > > Sent: Wednesday, January 30, 2019 12:59 AM > > To: Mani, Rajmohan > > Cc: Mauro Carvalho Chehab ; Greg Kroah-Hartman > > ; linux-me...@vger.kernel.org; > > de...@driverdev.osuosl.org; linux-ker...@vger.kernel.org; Laurent Pinchart > > ; Jacopo Mondi ; > > Qiu, Tian Shu ; Cao, Bingbu > > ; z...@paasikivi.fi.intel.com; Zhi, Yong > > ; hverk...@xs4all.nl; tf...@chromium.org > > Subject: Re: [PATCH] media: staging/intel-ipu3: Implement lock for stream > > on/off operations > > > > Hi Rajmohan, > > > > On Tue, Jan 29, 2019 at 02:27:36PM -0800, Rajmohan Mani wrote: > > > Currently concurrent stream off operations on ImgU nodes are not > > > synchronized, leading to use-after-free bugs (as reported by KASAN). > > > > > > [ 250.090724] BUG: KASAN: use-after-free in > > > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090726] Read of size 8 > > > at addr 888127b29bc0 by task yavta/18836 [ 250.090731] Hardware > > > name: HP Soraka/Soraka, BIOS Google_Soraka.10431.17.0 03/22/2018 [ > > 250.090732] Call Trace: > > > [ 250.090735] dump_stack+0x6a/0xb1 > > > [ 250.090739] print_address_description+0x8e/0x279 > > > [ 250.090743] ? ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ > > > 250.090746] kasan_report+0x260/0x28a [ 250.090750] > > > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090754] > > > ipu3_css_pool_cleanup+0x24/0x37 [ipu3_imgu] [ 250.090759] > > > ipu3_css_pipeline_cleanup+0x61/0xb9 [ipu3_imgu] [ 250.090763] > > > ipu3_css_stop_streaming+0x1f2/0x321 [ipu3_imgu] [ 250.090768] > > > imgu_s_stream+0x94/0x443 [ipu3_imgu] [ 250.090772] ? > > > ipu3_vb2_buf_queue+0x280/0x280 [ipu3_imgu] [ 250.090775] ? > > > vb2_dma_sg_unmap_dmabuf+0x16/0x6f [videobuf2_dma_sg] [ 250.090778] > > ? > > > vb2_buffer_in_use+0x36/0x58 [videobuf2_common] [ 250.090782] > > > ipu3_vb2_stop_streaming+0xf9/0x135 [ipu3_imgu] > > > > > > Implemented a lock to synchronize imgu stream on / off operations and > > > the modification of streaming flag (in struct imgu_device), to prevent > > > these issues. > > > > > > Reported-by: Laurent Pinchart > > > Suggested-by: Laurent Pinchart > > > > > > Signed-off-by: Rajmohan Mani > > > --- > > > drivers/staging/media/ipu3/ipu3-v4l2.c | 6 ++ > > > drivers/staging/media/ipu3/ipu3.c | 3 +++ > > > drivers/staging/media/ipu3/ipu3.h | 4 > > > 3 files changed, 13 insertions(+) > > > > > > diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c > > > b/drivers/staging/media/ipu3/ipu3-v4l2.c > > > index c7936032beb9..cf7e917cd0c8 100644 > > > --- a/drivers/staging/media/ipu3/ipu3-v4l2.c > > > +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c > > > @@ -507,12 +507,15 @@ static int ipu3_vb2_start_streaming(struct > > vb2_queue *vq, unsigned int count) > > > goto fail_stop_pipeline; > > > } > > > > > > + mutex_lock(>streaming_lock); > > > + > > > > You appear to be using imgu_device.lock (while searching buffers to queue to > > the device) as well as imgu_video_device.lock (qbuf, dqbuf) to serialise > > access > > to imgu_video_device.buffers list. > > Ack > > > The two locks may be acquired at the same > > time but each by different processes. That needs to be addressed, but > > probably not in this patch. > > > > The node specific locks will be used by different processes and all of these > processes > will be competing commonly (and successfully) for the imgu_device lock. > I will look into this more. Oops. I think I must have misread something; looking at the code again, indeed imgu_device.lock is acquired for all accesses. Please ignore this comment. > > > I wonder if it'd be more simple to use imgu->lock here instead of adding a > > new > > one. > > > > Extending imgu->lock here, does not work in this case, as imgu_queue_buffers() > will be stuck acquiring imgu->lock, which was already acquired by > imgu_s_stream() > through ipu3_vb2_start_streaming(). > > > > /* Start streaming of the whole pipeline now */ > > > dev_dbg(dev, "IMGU streaming is ready to start"); > > > r = imgu_s_stream(imgu, true); > > > if (!r) > > >
RE: [PATCH] media: staging/intel-ipu3: Implement lock for stream on/off operations
Hi Sakari,
> -Original Message-
> From: Sakari Ailus [mailto:sakari.ai...@linux.intel.com]
> Sent: Wednesday, January 30, 2019 12:59 AM
> To: Mani, Rajmohan
> Cc: Mauro Carvalho Chehab ; Greg Kroah-Hartman
> ; linux-me...@vger.kernel.org;
> de...@driverdev.osuosl.org; linux-ker...@vger.kernel.org; Laurent Pinchart
> ; Jacopo Mondi ;
> Qiu, Tian Shu ; Cao, Bingbu
> ; z...@paasikivi.fi.intel.com; Zhi, Yong
> ; hverk...@xs4all.nl; tf...@chromium.org
> Subject: Re: [PATCH] media: staging/intel-ipu3: Implement lock for stream
> on/off operations
>
> Hi Rajmohan,
>
> On Tue, Jan 29, 2019 at 02:27:36PM -0800, Rajmohan Mani wrote:
> > Currently concurrent stream off operations on ImgU nodes are not
> > synchronized, leading to use-after-free bugs (as reported by KASAN).
> >
> > [ 250.090724] BUG: KASAN: use-after-free in
> > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090726] Read of size 8
> > at addr 888127b29bc0 by task yavta/18836 [ 250.090731] Hardware
> > name: HP Soraka/Soraka, BIOS Google_Soraka.10431.17.0 03/22/2018 [
> 250.090732] Call Trace:
> > [ 250.090735] dump_stack+0x6a/0xb1
> > [ 250.090739] print_address_description+0x8e/0x279
> > [ 250.090743] ? ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [
> > 250.090746] kasan_report+0x260/0x28a [ 250.090750]
> > ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu] [ 250.090754]
> > ipu3_css_pool_cleanup+0x24/0x37 [ipu3_imgu] [ 250.090759]
> > ipu3_css_pipeline_cleanup+0x61/0xb9 [ipu3_imgu] [ 250.090763]
> > ipu3_css_stop_streaming+0x1f2/0x321 [ipu3_imgu] [ 250.090768]
> > imgu_s_stream+0x94/0x443 [ipu3_imgu] [ 250.090772] ?
> > ipu3_vb2_buf_queue+0x280/0x280 [ipu3_imgu] [ 250.090775] ?
> > vb2_dma_sg_unmap_dmabuf+0x16/0x6f [videobuf2_dma_sg] [ 250.090778]
> ?
> > vb2_buffer_in_use+0x36/0x58 [videobuf2_common] [ 250.090782]
> > ipu3_vb2_stop_streaming+0xf9/0x135 [ipu3_imgu]
> >
> > Implemented a lock to synchronize imgu stream on / off operations and
> > the modification of streaming flag (in struct imgu_device), to prevent
> > these issues.
> >
> > Reported-by: Laurent Pinchart
> > Suggested-by: Laurent Pinchart
> >
> > Signed-off-by: Rajmohan Mani
> > ---
> > drivers/staging/media/ipu3/ipu3-v4l2.c | 6 ++
> > drivers/staging/media/ipu3/ipu3.c | 3 +++
> > drivers/staging/media/ipu3/ipu3.h | 4
> > 3 files changed, 13 insertions(+)
> >
> > diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c
> > b/drivers/staging/media/ipu3/ipu3-v4l2.c
> > index c7936032beb9..cf7e917cd0c8 100644
> > --- a/drivers/staging/media/ipu3/ipu3-v4l2.c
> > +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c
> > @@ -507,12 +507,15 @@ static int ipu3_vb2_start_streaming(struct
> vb2_queue *vq, unsigned int count)
> > goto fail_stop_pipeline;
> > }
> >
> > + mutex_lock(>streaming_lock);
> > +
>
> You appear to be using imgu_device.lock (while searching buffers to queue to
> the device) as well as imgu_video_device.lock (qbuf, dqbuf) to serialise
> access
> to imgu_video_device.buffers list.
Ack
> The two locks may be acquired at the same
> time but each by different processes. That needs to be addressed, but
> probably not in this patch.
>
The node specific locks will be used by different processes and all of these
processes
will be competing commonly (and successfully) for the imgu_device lock.
I will look into this more.
> I wonder if it'd be more simple to use imgu->lock here instead of adding a new
> one.
>
Extending imgu->lock here, does not work in this case, as imgu_queue_buffers()
will be stuck acquiring imgu->lock, which was already acquired by
imgu_s_stream()
through ipu3_vb2_start_streaming().
> > /* Start streaming of the whole pipeline now */
> > dev_dbg(dev, "IMGU streaming is ready to start");
> > r = imgu_s_stream(imgu, true);
> > if (!r)
> > imgu->streaming = true;
> >
> > + mutex_unlock(>streaming_lock);
> > return 0;
> >
> > fail_stop_pipeline:
> > @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct
> vb2_queue *vq)
> > dev_err(>pci_dev->dev,
> > "failed to stop subdev streaming\n");
> >
> > + mutex_lock(>streaming_lock);
> > +
> > /* Was this the first node with streaming disabled? */
> > if (imgu->streaming && ipu3_all_nodes_streaming(imgu, node)) {
> > /* Yes, really stop streaming now */ @@ -552,6 +557,7 @@
> static
> > void ipu3_vb
Re: [PATCH] media: staging/intel-ipu3: Implement lock for stream on/off operations
Hi Rajmohan,
On Tue, Jan 29, 2019 at 02:27:36PM -0800, Rajmohan Mani wrote:
> Currently concurrent stream off operations on ImgU nodes are not
> synchronized, leading to use-after-free bugs (as reported by KASAN).
>
> [ 250.090724] BUG: KASAN: use-after-free in ipu3_dmamap_free+0xc5/0x116
> [ipu3_imgu]
> [ 250.090726] Read of size 8 at addr 888127b29bc0 by task yavta/18836
> [ 250.090731] Hardware name: HP Soraka/Soraka, BIOS Google_Soraka.10431.17.0
> 03/22/2018
> [ 250.090732] Call Trace:
> [ 250.090735] dump_stack+0x6a/0xb1
> [ 250.090739] print_address_description+0x8e/0x279
> [ 250.090743] ? ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu]
> [ 250.090746] kasan_report+0x260/0x28a
> [ 250.090750] ipu3_dmamap_free+0xc5/0x116 [ipu3_imgu]
> [ 250.090754] ipu3_css_pool_cleanup+0x24/0x37 [ipu3_imgu]
> [ 250.090759] ipu3_css_pipeline_cleanup+0x61/0xb9 [ipu3_imgu]
> [ 250.090763] ipu3_css_stop_streaming+0x1f2/0x321 [ipu3_imgu]
> [ 250.090768] imgu_s_stream+0x94/0x443 [ipu3_imgu]
> [ 250.090772] ? ipu3_vb2_buf_queue+0x280/0x280 [ipu3_imgu]
> [ 250.090775] ? vb2_dma_sg_unmap_dmabuf+0x16/0x6f [videobuf2_dma_sg]
> [ 250.090778] ? vb2_buffer_in_use+0x36/0x58 [videobuf2_common]
> [ 250.090782] ipu3_vb2_stop_streaming+0xf9/0x135 [ipu3_imgu]
>
> Implemented a lock to synchronize imgu stream on / off operations and
> the modification of streaming flag (in struct imgu_device), to prevent
> these issues.
>
> Reported-by: Laurent Pinchart
> Suggested-by: Laurent Pinchart
>
> Signed-off-by: Rajmohan Mani
> ---
> drivers/staging/media/ipu3/ipu3-v4l2.c | 6 ++
> drivers/staging/media/ipu3/ipu3.c | 3 +++
> drivers/staging/media/ipu3/ipu3.h | 4
> 3 files changed, 13 insertions(+)
>
> diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c
> b/drivers/staging/media/ipu3/ipu3-v4l2.c
> index c7936032beb9..cf7e917cd0c8 100644
> --- a/drivers/staging/media/ipu3/ipu3-v4l2.c
> +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c
> @@ -507,12 +507,15 @@ static int ipu3_vb2_start_streaming(struct vb2_queue
> *vq, unsigned int count)
> goto fail_stop_pipeline;
> }
>
> + mutex_lock(>streaming_lock);
> +
You appear to be using imgu_device.lock (while searching buffers to queue
to the device) as well as imgu_video_device.lock (qbuf, dqbuf) to serialise
access to imgu_video_device.buffers list. The two locks may be acquired at
the same time but each by different processes. That needs to be addressed,
but probably not in this patch.
I wonder if it'd be more simple to use imgu->lock here instead of adding a
new one.
> /* Start streaming of the whole pipeline now */
> dev_dbg(dev, "IMGU streaming is ready to start");
> r = imgu_s_stream(imgu, true);
> if (!r)
> imgu->streaming = true;
>
> + mutex_unlock(>streaming_lock);
> return 0;
>
> fail_stop_pipeline:
> @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct vb2_queue *vq)
> dev_err(>pci_dev->dev,
> "failed to stop subdev streaming\n");
>
> + mutex_lock(>streaming_lock);
> +
> /* Was this the first node with streaming disabled? */
> if (imgu->streaming && ipu3_all_nodes_streaming(imgu, node)) {
> /* Yes, really stop streaming now */
> @@ -552,6 +557,7 @@ static void ipu3_vb2_stop_streaming(struct vb2_queue *vq)
> imgu->streaming = false;
> }
>
> + mutex_unlock(>streaming_lock);
> ipu3_return_all_buffers(imgu, node, VB2_BUF_STATE_ERROR);
> media_pipeline_stop(>vdev.entity);
> }
> diff --git a/drivers/staging/media/ipu3/ipu3.c
> b/drivers/staging/media/ipu3/ipu3.c
> index d521b3afb8b1..2daee51cd845 100644
> --- a/drivers/staging/media/ipu3/ipu3.c
> +++ b/drivers/staging/media/ipu3/ipu3.c
> @@ -635,6 +635,7 @@ static int imgu_pci_probe(struct pci_dev *pci_dev,
> return r;
>
> mutex_init(>lock);
> + mutex_init(>streaming_lock);
> atomic_set(>qbuf_barrier, 0);
> init_waitqueue_head(>buf_drain_wq);
>
> @@ -699,6 +700,7 @@ static int imgu_pci_probe(struct pci_dev *pci_dev,
> ipu3_css_set_powerdown(_dev->dev, imgu->base);
> out_mutex_destroy:
> mutex_destroy(>lock);
> + mutex_destroy(>streaming_lock);
>
> return r;
> }
> @@ -716,6 +718,7 @@ static void imgu_pci_remove(struct pci_dev *pci_dev)
> ipu3_dmamap_exit(imgu);
> ipu3_mmu_exit(imgu->mmu);
> mutex_destroy(>lock);
> + mutex_destroy(>streaming_lock);
> }
>
> static int __maybe_unused imgu_suspend(struct device *dev)
> diff --git a/drivers/staging/media/ipu3/ipu3.h
> b/drivers/staging/media/ipu3/ipu3.h
> index 04fc99f47ebb..f732315f0701 100644
> --- a/drivers/staging/media/ipu3/ipu3.h
> +++ b/drivers/staging/media/ipu3/ipu3.h
> @@ -146,6 +146,10 @@ struct imgu_device {
>* vid_buf.list and css->queue
>*/
> struct mutex lock;
> +
> + /* Lock to protect writes to
