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 ffff888127b29bc0 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 <[email protected]>
Suggested-by: Laurent Pinchart <[email protected]>
Signed-off-by: Rajmohan Mani <[email protected]>
---
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(&imgu->streaming_lock);
+
/* 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(&imgu->streaming_lock);
return 0;
fail_stop_pipeline:
@@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct vb2_queue *vq)
dev_err(&imgu->pci_dev->dev,
"failed to stop subdev streaming\n");
+ mutex_lock(&imgu->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(&imgu->streaming_lock);
ipu3_return_all_buffers(imgu, node, VB2_BUF_STATE_ERROR);
media_pipeline_stop(&node->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(&imgu->lock);
+ mutex_init(&imgu->streaming_lock);
atomic_set(&imgu->qbuf_barrier, 0);
init_waitqueue_head(&imgu->buf_drain_wq);
@@ -699,6 +700,7 @@ static int imgu_pci_probe(struct pci_dev *pci_dev,
ipu3_css_set_powerdown(&pci_dev->dev, imgu->base);
out_mutex_destroy:
mutex_destroy(&imgu->lock);
+ mutex_destroy(&imgu->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(&imgu->lock);
+ mutex_destroy(&imgu->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 streaming flag in this struct */
+ struct mutex streaming_lock;
+
/* Forbit streaming and buffer queuing during system suspend. */
atomic_t qbuf_barrier;
/* Indicate if system suspend take place while imgu is streaming. */
--
2.19.1
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 ffff888127b29bc0 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 <[email protected]>
> Suggested-by: Laurent Pinchart <[email protected]>
>
> Signed-off-by: Rajmohan Mani <[email protected]>
> ---
> 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(&imgu->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(&imgu->streaming_lock);
> return 0;
>
> fail_stop_pipeline:
> @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct vb2_queue *vq)
> dev_err(&imgu->pci_dev->dev,
> "failed to stop subdev streaming\n");
>
> + mutex_lock(&imgu->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(&imgu->streaming_lock);
> ipu3_return_all_buffers(imgu, node, VB2_BUF_STATE_ERROR);
> media_pipeline_stop(&node->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(&imgu->lock);
> + mutex_init(&imgu->streaming_lock);
> atomic_set(&imgu->qbuf_barrier, 0);
> init_waitqueue_head(&imgu->buf_drain_wq);
>
> @@ -699,6 +700,7 @@ static int imgu_pci_probe(struct pci_dev *pci_dev,
> ipu3_css_set_powerdown(&pci_dev->dev, imgu->base);
> out_mutex_destroy:
> mutex_destroy(&imgu->lock);
> + mutex_destroy(&imgu->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(&imgu->lock);
> + mutex_destroy(&imgu->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 streaming flag in this struct */
> + struct mutex streaming_lock;
> +
> /* Forbit streaming and buffer queuing during system suspend. */
> atomic_t qbuf_barrier;
> /* Indicate if system suspend take place while imgu is streaming. */
--
Regards,
Sakari Ailus
[email protected]
Hi Sakari,
> -----Original Message-----
> From: Sakari Ailus [mailto:[email protected]]
> Sent: Wednesday, January 30, 2019 12:59 AM
> To: Mani, Rajmohan <[email protected]>
> Cc: Mauro Carvalho Chehab <[email protected]>; Greg Kroah-Hartman
> <[email protected]>; [email protected];
> [email protected]; [email protected]; Laurent Pinchart
> <[email protected]>; Jacopo Mondi <[email protected]>;
> Qiu, Tian Shu <[email protected]>; Cao, Bingbu
> <[email protected]>; [email protected]; Zhi, Yong
> <[email protected]>; [email protected]; [email protected]
> 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 ffff888127b29bc0 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 <[email protected]>
> > Suggested-by: Laurent Pinchart <[email protected]>
> >
> > Signed-off-by: Rajmohan Mani <[email protected]>
> > ---
> > 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(&imgu->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(&imgu->streaming_lock);
> > return 0;
> >
> > fail_stop_pipeline:
> > @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct
> vb2_queue *vq)
> > dev_err(&imgu->pci_dev->dev,
> > "failed to stop subdev streaming\n");
> >
> > + mutex_lock(&imgu->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(&imgu->streaming_lock);
> > ipu3_return_all_buffers(imgu, node, VB2_BUF_STATE_ERROR);
>
> > media_pipeline_stop(&node->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(&imgu->lock);
> > + mutex_init(&imgu->streaming_lock);
> > atomic_set(&imgu->qbuf_barrier, 0);
> > init_waitqueue_head(&imgu->buf_drain_wq);
> >
> > @@ -699,6 +700,7 @@ static int imgu_pci_probe(struct pci_dev *pci_dev,
> > ipu3_css_set_powerdown(&pci_dev->dev, imgu->base);
> > out_mutex_destroy:
> > mutex_destroy(&imgu->lock);
> > + mutex_destroy(&imgu->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(&imgu->lock);
> > + mutex_destroy(&imgu->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 streaming flag in this struct */
> > + struct mutex streaming_lock;
> > +
> > /* Forbit streaming and buffer queuing during system suspend. */
> > atomic_t qbuf_barrier;
> > /* Indicate if system suspend take place while imgu is streaming. */
>
> --
> Regards,
>
> Sakari Ailus
> [email protected]
Hi Raj,
On Wed, Jan 30, 2019 at 05:17:15PM +0000, Mani, Rajmohan wrote:
> Hi Sakari,
>
> > -----Original Message-----
> > From: Sakari Ailus [mailto:[email protected]]
> > Sent: Wednesday, January 30, 2019 12:59 AM
> > To: Mani, Rajmohan <[email protected]>
> > Cc: Mauro Carvalho Chehab <[email protected]>; Greg Kroah-Hartman
> > <[email protected]>; [email protected];
> > [email protected]; [email protected]; Laurent Pinchart
> > <[email protected]>; Jacopo Mondi <[email protected]>;
> > Qiu, Tian Shu <[email protected]>; Cao, Bingbu
> > <[email protected]>; [email protected]; Zhi, Yong
> > <[email protected]>; [email protected]; [email protected]
> > 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 ffff888127b29bc0 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 <[email protected]>
> > > Suggested-by: Laurent Pinchart <[email protected]>
> > >
> > > Signed-off-by: Rajmohan Mani <[email protected]>
> > > ---
> > > 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(&imgu->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)
> > > imgu->streaming = true;
> > >
> > > + mutex_unlock(&imgu->streaming_lock);
> > > return 0;
> > >
> > > fail_stop_pipeline:
> > > @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct
> > vb2_queue *vq)
> > > dev_err(&imgu->pci_dev->dev,
> > > "failed to stop subdev streaming\n");
> > >
> > > + mutex_lock(&imgu->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(&imgu->streaming_lock);
> > > ipu3_return_all_buffers(imgu, node, VB2_BUF_STATE_ERROR);
> >
> > > media_pipeline_stop(&node->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(&imgu->lock);
> > > + mutex_init(&imgu->streaming_lock);
> > > atomic_set(&imgu->qbuf_barrier, 0);
> > > init_waitqueue_head(&imgu->buf_drain_wq);
> > >
> > > @@ -699,6 +700,7 @@ static int imgu_pci_probe(struct pci_dev *pci_dev,
> > > ipu3_css_set_powerdown(&pci_dev->dev, imgu->base);
> > > out_mutex_destroy:
> > > mutex_destroy(&imgu->lock);
> > > + mutex_destroy(&imgu->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(&imgu->lock);
> > > + mutex_destroy(&imgu->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 streaming flag in this struct */
> > > + struct mutex streaming_lock;
> > > +
> > > /* Forbit streaming and buffer queuing during system suspend. */
> > > atomic_t qbuf_barrier;
> > > /* Indicate if system suspend take place while imgu is streaming. */
> >
> > --
> > Regards,
> >
> > Sakari Ailus
> > [email protected]
--
Sakari Ailus
[email protected]
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 +0000, Mani, Rajmohan wrote:
> > Hi Sakari,
> >
> > > -----Original Message-----
> > > From: Sakari Ailus [mailto:[email protected]]
> > > Sent: Wednesday, January 30, 2019 12:59 AM
> > > To: Mani, Rajmohan <[email protected]>
> > > Cc: Mauro Carvalho Chehab <[email protected]>; Greg Kroah-Hartman
> > > <[email protected]>; [email protected];
> > > [email protected]; [email protected]; Laurent
> > > Pinchart <[email protected]>; Jacopo Mondi
> > > <[email protected]>; Qiu, Tian Shu <[email protected]>; Cao,
> > > Bingbu <[email protected]>; [email protected]; Zhi, Yong
> > > <[email protected]>; [email protected]; [email protected]
> > > 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 ffff888127b29bc0 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 <[email protected]>
> > > > Suggested-by: Laurent Pinchart <[email protected]>
> > > >
> > > > Signed-off-by: Rajmohan Mani <[email protected]>
> > > > ---
> > > > 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(&imgu->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.
>
Ack. Let me look into this more.
> Can you grab the lock right after dev_dbg() line in the function?
>
In order to reduce the amount of code that's run with the lock held,
I placed the lock here.
Do you see issues in calls to imgu_sd subdevs and media_pipeline_start(),
without the lock being held?
> The lock should be also acquired before testing imgu->streaming in
> ipu3_vb2_buf_queue() to make sure it won't change in the meantime.
>
I thought about this and decided against this since the odds of multiple
instances of applications, each of which using a single node simultaneously
are less, in a typical camera use case.
Please confirm if you see significant issues without the lock here, so we can
add the lock here as well.
> >
> > > > /* 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(&imgu->streaming_lock);
> > > > return 0;
> > > >
> > > > fail_stop_pipeline:
> > > > @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct
> > > vb2_queue *vq)
> > > > dev_err(&imgu->pci_dev->dev,
> > > > "failed to stop subdev streaming\n");
> > > >
> > > > + mutex_lock(&imgu->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(&imgu->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.
>
> > >
> > > > media_pipeline_stop(&node->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(&imgu->lock);
> > > > + mutex_init(&imgu->streaming_lock);
> > > > atomic_set(&imgu->qbuf_barrier, 0);
> > > > init_waitqueue_head(&imgu->buf_drain_wq);
> > > >
> > > > @@ -699,6 +700,7 @@ static int imgu_pci_probe(struct pci_dev
> *pci_dev,
> > > > ipu3_css_set_powerdown(&pci_dev->dev, imgu->base);
> > > > out_mutex_destroy:
> > > > mutex_destroy(&imgu->lock);
> > > > + mutex_destroy(&imgu->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(&imgu->lock);
> > > > + mutex_destroy(&imgu->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 streaming flag in this struct */
> > > > + struct mutex streaming_lock;
> > > > +
> > > > /* Forbit streaming and buffer queuing during system suspend. */
> > > > atomic_t qbuf_barrier;
> > > > /* Indicate if system suspend take place while imgu is
> > > > streaming. */
> > >
>
> --
> Sakari Ailus
> [email protected]
Hi Sakari,
[snip]
> > > > > fail_stop_pipeline:
> > > > > @@ -543,6 +546,8 @@ static void ipu3_vb2_stop_streaming(struct
> > > > vb2_queue *vq)
> > > > > dev_err(&imgu->pci_dev->dev,
> > > > > "failed to stop subdev streaming\n");
> > > > >
> > > > > + mutex_lock(&imgu->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(&imgu->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]