usb drivers should not call to any usb_() function after the
.disconnect() callback has been triggered.
If the camera is streaming, the uvc driver will call usb_set_interface or
usb_clear_halt once the device is being released. Let's fix this issue.
This is probably not the only driver affected with this kind of bug, but
until there is a better way to do it in the core this is the way to
solve this issue.
When/if a different mechanism is implemented in the core to solve the
lifetime of devices we will adopt it in uvc.
Trace:
[ 1065.389723] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
[ 1065.390160] drivers/media/usb/uvc/uvc_driver.c:2264 uvc_disconnect exit
[ 1065.433956] drivers/media/usb/uvc/uvc_v4l2.c:659 uvc_v4l2_release enter
[ 1065.433973] drivers/media/usb/uvc/uvc_video.c:2274 uvc_video_stop_streaming enter
[ 1065.434560] drivers/media/usb/uvc/uvc_video.c:2285 uvc_video_stop_streaming exit
[ 1065.435154] drivers/media/usb/uvc/uvc_v4l2.c:680 uvc_v4l2_release exit
[ 1065.435188] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
Signed-off-by: Ricardo Ribalda <[email protected]>
---
drivers/media/usb/uvc/uvc_driver.c | 2 ++
drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++--------------
drivers/media/usb/uvc/uvcvideo.h | 2 ++
3 files changed, 32 insertions(+), 17 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 08fcd2ffa727..413c32867617 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2257,6 +2257,8 @@ static void uvc_disconnect(struct usb_interface *intf)
return;
uvc_unregister_video(dev);
+ /* Barrier needed to synchronize with uvc_video_stop_streaming(). */
+ smp_store_release(&dev->disconnected, true);
kref_put(&dev->ref, uvc_delete);
}
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 28dde08ec6c5..032b44e45b22 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -2243,28 +2243,39 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
return ret;
}
-void uvc_video_stop_streaming(struct uvc_streaming *stream)
+static void uvc_video_halt(struct uvc_streaming *stream)
{
- uvc_video_stop_transfer(stream, 1);
+ unsigned int epnum;
+ unsigned int pipe;
+ unsigned int dir;
if (stream->intf->num_altsetting > 1) {
usb_set_interface(stream->dev->udev, stream->intfnum, 0);
- } else {
- /*
- * UVC doesn't specify how to inform a bulk-based device
- * when the video stream is stopped. Windows sends a
- * CLEAR_FEATURE(HALT) request to the video streaming
- * bulk endpoint, mimic the same behaviour.
- */
- unsigned int epnum = stream->header.bEndpointAddress
- & USB_ENDPOINT_NUMBER_MASK;
- unsigned int dir = stream->header.bEndpointAddress
- & USB_ENDPOINT_DIR_MASK;
- unsigned int pipe;
-
- pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
- usb_clear_halt(stream->dev->udev, pipe);
+ return;
}
+ /*
+ * UVC doesn't specify how to inform a bulk-based device
+ * when the video stream is stopped. Windows sends a
+ * CLEAR_FEATURE(HALT) request to the video streaming
+ * bulk endpoint, mimic the same behaviour.
+ */
+ epnum = stream->header.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
+ dir = stream->header.bEndpointAddress & USB_ENDPOINT_DIR_MASK;
+ pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
+ usb_clear_halt(stream->dev->udev, pipe);
+}
+
+void uvc_video_stop_streaming(struct uvc_streaming *stream)
+{
+ uvc_video_stop_transfer(stream, 1);
+
+ /*
+ * Barrier needed to synchronize with uvc_disconnect().
+ * We cannot call usb_* functions on a disconnected USB device.
+ */
+ if (!smp_load_acquire(&stream->dev->disconnected))
+ uvc_video_halt(stream);
+
uvc_video_clock_cleanup(stream);
}
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 6fb0a78b1b00..4318ce8e31db 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -559,6 +559,8 @@ struct uvc_device {
unsigned int users;
atomic_t nmappings;
+ bool disconnected;
+
/* Video control interface */
#ifdef CONFIG_MEDIA_CONTROLLER
struct media_device mdev;
--
2.43.0.rc1.413.gea7ed67945-goog
On (23/11/21 19:53), Ricardo Ribalda wrote:
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 08fcd2ffa727..413c32867617 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -2257,6 +2257,8 @@ static void uvc_disconnect(struct usb_interface *intf)
> return;
>
> uvc_unregister_video(dev);
> + /* Barrier needed to synchronize with uvc_video_stop_streaming(). */
> + smp_store_release(&dev->disconnected, true);
> kref_put(&dev->ref, uvc_delete);
> }
[..]
> +void uvc_video_stop_streaming(struct uvc_streaming *stream)
> +{
> + uvc_video_stop_transfer(stream, 1);
> +
> + /*
> + * Barrier needed to synchronize with uvc_disconnect().
> + * We cannot call usb_* functions on a disconnected USB device.
> + */
> + if (!smp_load_acquire(&stream->dev->disconnected))
> + uvc_video_halt(stream);
> +
> uvc_video_clock_cleanup(stream);
> }
Can the following happen?
CPU0 CPU1
uvc_disconnect()
uvc_video_stop_streaming()
usb_set_intfdata()
uvc_unregister_video()
if (!smp_load(&dev->disconnected))
uvc_video_halt()
smp_store_release(&dev->disconnected, true);
kref_put(&dev->ref, uvc_delete);
On (23/11/22 16:47), Sergey Senozhatsky wrote:
> Can the following happen?
Consider the following case (when CPU1 experienced a delay, a preemption
or anything):
> CPU0 CPU1
> uvc_disconnect()
> uvc_video_stop_streaming()
> usb_set_intfdata()
> uvc_unregister_video()
>
> if (!smp_load(&dev->disconnected))
>
> smp_store_release(&dev->disconnected, true);
>
> kref_put(&dev->ref, uvc_delete);
> uvc_video_halt()
That uvc_video_halt() cannot be legal, right?
Hi Sergey
On Wed, 22 Nov 2023 at 09:01, Sergey Senozhatsky
<[email protected]> wrote:
>
> On (23/11/22 16:47), Sergey Senozhatsky wrote:
> > Can the following happen?
>
> Consider the following case (when CPU1 experienced a delay, a preemption
> or anything):
>
> > CPU0 CPU1
> > uvc_disconnect()
> > uvc_video_stop_streaming()
> > usb_set_intfdata()
> > uvc_unregister_video()
> >
> > if (!smp_load(&dev->disconnected))
> >
> > smp_store_release(&dev->disconnected, true);
> >
> > kref_put(&dev->ref, uvc_delete);
>
> > uvc_video_halt()
>
> That uvc_video_halt() cannot be legal, right?
This patch only takes care of calls to uvc_video_stop_streaming()
after .disconnect.
Guenter's patch from this series should take care of the concurrent
calls. I will resend making it explicit.
Thanks!
--
Ricardo Ribalda
Hi Sakari
On Wed, 22 Nov 2023 at 11:25, Sakari Ailus <[email protected]> wrote:
>
> Hi Ricardo,
>
> Thank you for the patch.
>
> On Tue, Nov 21, 2023 at 07:53:49PM +0000, Ricardo Ribalda wrote:
> > usb drivers should not call to any usb_() function after the
> > .disconnect() callback has been triggered.
> >
> > If the camera is streaming, the uvc driver will call usb_set_interface or
> > usb_clear_halt once the device is being released. Let's fix this issue.
> >
> > This is probably not the only driver affected with this kind of bug, but
> > until there is a better way to do it in the core this is the way to
> > solve this issue.
> >
> > When/if a different mechanism is implemented in the core to solve the
> > lifetime of devices we will adopt it in uvc.
> >
> > Trace:
> > [ 1065.389723] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
> > [ 1065.390160] drivers/media/usb/uvc/uvc_driver.c:2264 uvc_disconnect exit
> > [ 1065.433956] drivers/media/usb/uvc/uvc_v4l2.c:659 uvc_v4l2_release enter
> > [ 1065.433973] drivers/media/usb/uvc/uvc_video.c:2274 uvc_video_stop_streaming enter
> > [ 1065.434560] drivers/media/usb/uvc/uvc_video.c:2285 uvc_video_stop_streaming exit
> > [ 1065.435154] drivers/media/usb/uvc/uvc_v4l2.c:680 uvc_v4l2_release exit
> > [ 1065.435188] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
> >
> > Signed-off-by: Ricardo Ribalda <[email protected]>
> > ---
> > drivers/media/usb/uvc/uvc_driver.c | 2 ++
> > drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++--------------
> > drivers/media/usb/uvc/uvcvideo.h | 2 ++
> > 3 files changed, 32 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > index 08fcd2ffa727..413c32867617 100644
> > --- a/drivers/media/usb/uvc/uvc_driver.c
> > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > @@ -2257,6 +2257,8 @@ static void uvc_disconnect(struct usb_interface *intf)
> > return;
> >
> > uvc_unregister_video(dev);
> > + /* Barrier needed to synchronize with uvc_video_stop_streaming(). */
> > + smp_store_release(&dev->disconnected, true);
> > kref_put(&dev->ref, uvc_delete);
> > }
> >
> > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > index 28dde08ec6c5..032b44e45b22 100644
> > --- a/drivers/media/usb/uvc/uvc_video.c
> > +++ b/drivers/media/usb/uvc/uvc_video.c
> > @@ -2243,28 +2243,39 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
> > return ret;
> > }
> >
> > -void uvc_video_stop_streaming(struct uvc_streaming *stream)
> > +static void uvc_video_halt(struct uvc_streaming *stream)
> > {
> > - uvc_video_stop_transfer(stream, 1);
> > + unsigned int epnum;
> > + unsigned int pipe;
> > + unsigned int dir;
> >
> > if (stream->intf->num_altsetting > 1) {
>
> Doesn't this imply the device is using isochronous mode?
I haven't changed the behaviour for halt, it is just that git diff is
being a bit too creative here:
Basically it is doing:
void video_halt() {
if (is_isoc()) {
usb_set_interface(stream->dev->udev, stream->intfnum, 0);
return;
}
usb_clear_halt();
}
instead of the old:
void video_halt() {
if (is_isoc()) {
usb_set_interface(stream->dev->udev, stream->intfnum, 0);
} else {
usb_clear_halt();
}
}
Thanks!
>
> > usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> > - } else {
> > - /*
> > - * UVC doesn't specify how to inform a bulk-based device
> > - * when the video stream is stopped. Windows sends a
> > - * CLEAR_FEATURE(HALT) request to the video streaming
> > - * bulk endpoint, mimic the same behaviour.
> > - */
> > - unsigned int epnum = stream->header.bEndpointAddress
> > - & USB_ENDPOINT_NUMBER_MASK;
> > - unsigned int dir = stream->header.bEndpointAddress
> > - & USB_ENDPOINT_DIR_MASK;
> > - unsigned int pipe;
> > -
> > - pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> > - usb_clear_halt(stream->dev->udev, pipe);
> > + return;
> > }
> >
> > + /*
> > + * UVC doesn't specify how to inform a bulk-based device
>
> Then this comment doesn't look right. What about the code? This isn't
> mentioned in the commit message either.
>
> > + * when the video stream is stopped. Windows sends a
> > + * CLEAR_FEATURE(HALT) request to the video streaming
> > + * bulk endpoint, mimic the same behaviour.
> > + */
> > + epnum = stream->header.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
> > + dir = stream->header.bEndpointAddress & USB_ENDPOINT_DIR_MASK;
> > + pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> > + usb_clear_halt(stream->dev->udev, pipe);
> > +}
> > +
> > +void uvc_video_stop_streaming(struct uvc_streaming *stream)
> > +{
> > + uvc_video_stop_transfer(stream, 1);
> > +
> > + /*
> > + * Barrier needed to synchronize with uvc_disconnect().
> > + * We cannot call usb_* functions on a disconnected USB device.
> > + */
> > + if (!smp_load_acquire(&stream->dev->disconnected))
> > + uvc_video_halt(stream);
> > +
> > uvc_video_clock_cleanup(stream);
> > }
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index 6fb0a78b1b00..4318ce8e31db 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -559,6 +559,8 @@ struct uvc_device {
> > unsigned int users;
> > atomic_t nmappings;
> >
> > + bool disconnected;
> > +
> > /* Video control interface */
> > #ifdef CONFIG_MEDIA_CONTROLLER
> > struct media_device mdev;
> >
>
> --
> Kind regards,
>
> Sakari Ailus
--
Ricardo Ribalda
Hi
On Wed, 22 Nov 2023 at 12:04, Sakari Ailus <[email protected]> wrote:
>
> Hi Ricardo,
>
> On Wed, Nov 22, 2023 at 11:32:16AM +0100, Ricardo Ribalda wrote:
> > Hi Sakari
> >
> > On Wed, 22 Nov 2023 at 11:25, Sakari Ailus <[email protected]> wrote:
> > >
> > > Hi Ricardo,
> > >
> > > Thank you for the patch.
> > >
> > > On Tue, Nov 21, 2023 at 07:53:49PM +0000, Ricardo Ribalda wrote:
> > > > usb drivers should not call to any usb_() function after the
> > > > .disconnect() callback has been triggered.
> > > >
> > > > If the camera is streaming, the uvc driver will call usb_set_interface or
> > > > usb_clear_halt once the device is being released. Let's fix this issue.
> > > >
> > > > This is probably not the only driver affected with this kind of bug, but
> > > > until there is a better way to do it in the core this is the way to
> > > > solve this issue.
> > > >
> > > > When/if a different mechanism is implemented in the core to solve the
> > > > lifetime of devices we will adopt it in uvc.
> > > >
> > > > Trace:
> > > > [ 1065.389723] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
> > > > [ 1065.390160] drivers/media/usb/uvc/uvc_driver.c:2264 uvc_disconnect exit
> > > > [ 1065.433956] drivers/media/usb/uvc/uvc_v4l2.c:659 uvc_v4l2_release enter
> > > > [ 1065.433973] drivers/media/usb/uvc/uvc_video.c:2274 uvc_video_stop_streaming enter
> > > > [ 1065.434560] drivers/media/usb/uvc/uvc_video.c:2285 uvc_video_stop_streaming exit
> > > > [ 1065.435154] drivers/media/usb/uvc/uvc_v4l2.c:680 uvc_v4l2_release exit
> > > > [ 1065.435188] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
> > > >
> > > > Signed-off-by: Ricardo Ribalda <[email protected]>
> > > > ---
> > > > drivers/media/usb/uvc/uvc_driver.c | 2 ++
> > > > drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++--------------
> > > > drivers/media/usb/uvc/uvcvideo.h | 2 ++
> > > > 3 files changed, 32 insertions(+), 17 deletions(-)
> > > >
> > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > > > index 08fcd2ffa727..413c32867617 100644
> > > > --- a/drivers/media/usb/uvc/uvc_driver.c
> > > > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > > > @@ -2257,6 +2257,8 @@ static void uvc_disconnect(struct usb_interface *intf)
> > > > return;
> > > >
> > > > uvc_unregister_video(dev);
> > > > + /* Barrier needed to synchronize with uvc_video_stop_streaming(). */
> > > > + smp_store_release(&dev->disconnected, true);
> > > > kref_put(&dev->ref, uvc_delete);
> > > > }
> > > >
> > > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > > > index 28dde08ec6c5..032b44e45b22 100644
> > > > --- a/drivers/media/usb/uvc/uvc_video.c
> > > > +++ b/drivers/media/usb/uvc/uvc_video.c
> > > > @@ -2243,28 +2243,39 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
> > > > return ret;
> > > > }
> > > >
> > > > -void uvc_video_stop_streaming(struct uvc_streaming *stream)
> > > > +static void uvc_video_halt(struct uvc_streaming *stream)
> > > > {
> > > > - uvc_video_stop_transfer(stream, 1);
> > > > + unsigned int epnum;
> > > > + unsigned int pipe;
> > > > + unsigned int dir;
> > > >
> > > > if (stream->intf->num_altsetting > 1) {
> > >
> > > Doesn't this imply the device is using isochronous mode?
> >
> > I haven't changed the behaviour for halt, it is just that git diff is
> > being a bit too creative here:
> >
> > Basically it is doing:
> >
> > void video_halt() {
> > if (is_isoc()) {
> > usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> > return;
> > }
> > usb_clear_halt();
> > }
> >
> > instead of the old:
> >
> > void video_halt() {
> > if (is_isoc()) {
> > usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> > } else {
> > usb_clear_halt();
> > }
> > }
> >
> > Thanks!
>
> Oops. I missed the removal of the else branch altogether while reading the
> patch.
>
> Shouldn't you also ensure the disconnect callback won't return until the
> streaming has been stopped here?
This patch is just for calls after .disconnect. It will not protect
for concurrent calls.
I have sent a v4 making this explicit. We still need:
media: uvcvideo: Lock video streams and queues while unregistering
or similar.
Thanks!
>
> > >
> > > > usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> > > > - } else {
> > > > - /*
> > > > - * UVC doesn't specify how to inform a bulk-based device
> > > > - * when the video stream is stopped. Windows sends a
> > > > - * CLEAR_FEATURE(HALT) request to the video streaming
> > > > - * bulk endpoint, mimic the same behaviour.
> > > > - */
> > > > - unsigned int epnum = stream->header.bEndpointAddress
> > > > - & USB_ENDPOINT_NUMBER_MASK;
> > > > - unsigned int dir = stream->header.bEndpointAddress
> > > > - & USB_ENDPOINT_DIR_MASK;
> > > > - unsigned int pipe;
> > > > -
> > > > - pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> > > > - usb_clear_halt(stream->dev->udev, pipe);
> > > > + return;
> > > > }
> > > >
> > > > + /*
> > > > + * UVC doesn't specify how to inform a bulk-based device
> > >
> > > Then this comment doesn't look right. What about the code? This isn't
> > > mentioned in the commit message either.
> > >
> > > > + * when the video stream is stopped. Windows sends a
> > > > + * CLEAR_FEATURE(HALT) request to the video streaming
> > > > + * bulk endpoint, mimic the same behaviour.
> > > > + */
> > > > + epnum = stream->header.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
> > > > + dir = stream->header.bEndpointAddress & USB_ENDPOINT_DIR_MASK;
> > > > + pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> > > > + usb_clear_halt(stream->dev->udev, pipe);
> > > > +}
> > > > +
> > > > +void uvc_video_stop_streaming(struct uvc_streaming *stream)
> > > > +{
> > > > + uvc_video_stop_transfer(stream, 1);
> > > > +
> > > > + /*
> > > > + * Barrier needed to synchronize with uvc_disconnect().
> > > > + * We cannot call usb_* functions on a disconnected USB device.
> > > > + */
> > > > + if (!smp_load_acquire(&stream->dev->disconnected))
> > > > + uvc_video_halt(stream);
> > > > +
> > > > uvc_video_clock_cleanup(stream);
> > > > }
> > > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > > > index 6fb0a78b1b00..4318ce8e31db 100644
> > > > --- a/drivers/media/usb/uvc/uvcvideo.h
> > > > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > > > @@ -559,6 +559,8 @@ struct uvc_device {
> > > > unsigned int users;
> > > > atomic_t nmappings;
> > > >
> > > > + bool disconnected;
> > > > +
> > > > /* Video control interface */
> > > > #ifdef CONFIG_MEDIA_CONTROLLER
> > > > struct media_device mdev;
>
> --
> Kind regards,
>
> Sakari Ailus
--
Ricardo Ribalda
Hi Ricardo,
On Wed, Nov 22, 2023 at 11:32:16AM +0100, Ricardo Ribalda wrote:
> Hi Sakari
>
> On Wed, 22 Nov 2023 at 11:25, Sakari Ailus <[email protected]> wrote:
> >
> > Hi Ricardo,
> >
> > Thank you for the patch.
> >
> > On Tue, Nov 21, 2023 at 07:53:49PM +0000, Ricardo Ribalda wrote:
> > > usb drivers should not call to any usb_() function after the
> > > .disconnect() callback has been triggered.
> > >
> > > If the camera is streaming, the uvc driver will call usb_set_interface or
> > > usb_clear_halt once the device is being released. Let's fix this issue.
> > >
> > > This is probably not the only driver affected with this kind of bug, but
> > > until there is a better way to do it in the core this is the way to
> > > solve this issue.
> > >
> > > When/if a different mechanism is implemented in the core to solve the
> > > lifetime of devices we will adopt it in uvc.
> > >
> > > Trace:
> > > [ 1065.389723] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
> > > [ 1065.390160] drivers/media/usb/uvc/uvc_driver.c:2264 uvc_disconnect exit
> > > [ 1065.433956] drivers/media/usb/uvc/uvc_v4l2.c:659 uvc_v4l2_release enter
> > > [ 1065.433973] drivers/media/usb/uvc/uvc_video.c:2274 uvc_video_stop_streaming enter
> > > [ 1065.434560] drivers/media/usb/uvc/uvc_video.c:2285 uvc_video_stop_streaming exit
> > > [ 1065.435154] drivers/media/usb/uvc/uvc_v4l2.c:680 uvc_v4l2_release exit
> > > [ 1065.435188] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
> > >
> > > Signed-off-by: Ricardo Ribalda <[email protected]>
> > > ---
> > > drivers/media/usb/uvc/uvc_driver.c | 2 ++
> > > drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++--------------
> > > drivers/media/usb/uvc/uvcvideo.h | 2 ++
> > > 3 files changed, 32 insertions(+), 17 deletions(-)
> > >
> > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > > index 08fcd2ffa727..413c32867617 100644
> > > --- a/drivers/media/usb/uvc/uvc_driver.c
> > > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > > @@ -2257,6 +2257,8 @@ static void uvc_disconnect(struct usb_interface *intf)
> > > return;
> > >
> > > uvc_unregister_video(dev);
> > > + /* Barrier needed to synchronize with uvc_video_stop_streaming(). */
> > > + smp_store_release(&dev->disconnected, true);
> > > kref_put(&dev->ref, uvc_delete);
> > > }
> > >
> > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > > index 28dde08ec6c5..032b44e45b22 100644
> > > --- a/drivers/media/usb/uvc/uvc_video.c
> > > +++ b/drivers/media/usb/uvc/uvc_video.c
> > > @@ -2243,28 +2243,39 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
> > > return ret;
> > > }
> > >
> > > -void uvc_video_stop_streaming(struct uvc_streaming *stream)
> > > +static void uvc_video_halt(struct uvc_streaming *stream)
> > > {
> > > - uvc_video_stop_transfer(stream, 1);
> > > + unsigned int epnum;
> > > + unsigned int pipe;
> > > + unsigned int dir;
> > >
> > > if (stream->intf->num_altsetting > 1) {
> >
> > Doesn't this imply the device is using isochronous mode?
>
> I haven't changed the behaviour for halt, it is just that git diff is
> being a bit too creative here:
>
> Basically it is doing:
>
> void video_halt() {
> if (is_isoc()) {
> usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> return;
> }
> usb_clear_halt();
> }
>
> instead of the old:
>
> void video_halt() {
> if (is_isoc()) {
> usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> } else {
> usb_clear_halt();
> }
> }
>
> Thanks!
Oops. I missed the removal of the else branch altogether while reading the
patch.
Shouldn't you also ensure the disconnect callback won't return until the
streaming has been stopped here?
> >
> > > usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> > > - } else {
> > > - /*
> > > - * UVC doesn't specify how to inform a bulk-based device
> > > - * when the video stream is stopped. Windows sends a
> > > - * CLEAR_FEATURE(HALT) request to the video streaming
> > > - * bulk endpoint, mimic the same behaviour.
> > > - */
> > > - unsigned int epnum = stream->header.bEndpointAddress
> > > - & USB_ENDPOINT_NUMBER_MASK;
> > > - unsigned int dir = stream->header.bEndpointAddress
> > > - & USB_ENDPOINT_DIR_MASK;
> > > - unsigned int pipe;
> > > -
> > > - pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> > > - usb_clear_halt(stream->dev->udev, pipe);
> > > + return;
> > > }
> > >
> > > + /*
> > > + * UVC doesn't specify how to inform a bulk-based device
> >
> > Then this comment doesn't look right. What about the code? This isn't
> > mentioned in the commit message either.
> >
> > > + * when the video stream is stopped. Windows sends a
> > > + * CLEAR_FEATURE(HALT) request to the video streaming
> > > + * bulk endpoint, mimic the same behaviour.
> > > + */
> > > + epnum = stream->header.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
> > > + dir = stream->header.bEndpointAddress & USB_ENDPOINT_DIR_MASK;
> > > + pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> > > + usb_clear_halt(stream->dev->udev, pipe);
> > > +}
> > > +
> > > +void uvc_video_stop_streaming(struct uvc_streaming *stream)
> > > +{
> > > + uvc_video_stop_transfer(stream, 1);
> > > +
> > > + /*
> > > + * Barrier needed to synchronize with uvc_disconnect().
> > > + * We cannot call usb_* functions on a disconnected USB device.
> > > + */
> > > + if (!smp_load_acquire(&stream->dev->disconnected))
> > > + uvc_video_halt(stream);
> > > +
> > > uvc_video_clock_cleanup(stream);
> > > }
> > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > > index 6fb0a78b1b00..4318ce8e31db 100644
> > > --- a/drivers/media/usb/uvc/uvcvideo.h
> > > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > > @@ -559,6 +559,8 @@ struct uvc_device {
> > > unsigned int users;
> > > atomic_t nmappings;
> > >
> > > + bool disconnected;
> > > +
> > > /* Video control interface */
> > > #ifdef CONFIG_MEDIA_CONTROLLER
> > > struct media_device mdev;
--
Kind regards,
Sakari Ailus
Hi Ricardo,
Thank you for the patch.
On Tue, Nov 21, 2023 at 07:53:49PM +0000, Ricardo Ribalda wrote:
> usb drivers should not call to any usb_() function after the
> .disconnect() callback has been triggered.
>
> If the camera is streaming, the uvc driver will call usb_set_interface or
> usb_clear_halt once the device is being released. Let's fix this issue.
>
> This is probably not the only driver affected with this kind of bug, but
> until there is a better way to do it in the core this is the way to
> solve this issue.
>
> When/if a different mechanism is implemented in the core to solve the
> lifetime of devices we will adopt it in uvc.
>
> Trace:
> [ 1065.389723] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
> [ 1065.390160] drivers/media/usb/uvc/uvc_driver.c:2264 uvc_disconnect exit
> [ 1065.433956] drivers/media/usb/uvc/uvc_v4l2.c:659 uvc_v4l2_release enter
> [ 1065.433973] drivers/media/usb/uvc/uvc_video.c:2274 uvc_video_stop_streaming enter
> [ 1065.434560] drivers/media/usb/uvc/uvc_video.c:2285 uvc_video_stop_streaming exit
> [ 1065.435154] drivers/media/usb/uvc/uvc_v4l2.c:680 uvc_v4l2_release exit
> [ 1065.435188] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter
>
> Signed-off-by: Ricardo Ribalda <[email protected]>
> ---
> drivers/media/usb/uvc/uvc_driver.c | 2 ++
> drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++--------------
> drivers/media/usb/uvc/uvcvideo.h | 2 ++
> 3 files changed, 32 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 08fcd2ffa727..413c32867617 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -2257,6 +2257,8 @@ static void uvc_disconnect(struct usb_interface *intf)
> return;
>
> uvc_unregister_video(dev);
> + /* Barrier needed to synchronize with uvc_video_stop_streaming(). */
> + smp_store_release(&dev->disconnected, true);
> kref_put(&dev->ref, uvc_delete);
> }
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index 28dde08ec6c5..032b44e45b22 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -2243,28 +2243,39 @@ int uvc_video_start_streaming(struct uvc_streaming *stream)
> return ret;
> }
>
> -void uvc_video_stop_streaming(struct uvc_streaming *stream)
> +static void uvc_video_halt(struct uvc_streaming *stream)
> {
> - uvc_video_stop_transfer(stream, 1);
> + unsigned int epnum;
> + unsigned int pipe;
> + unsigned int dir;
>
> if (stream->intf->num_altsetting > 1) {
Doesn't this imply the device is using isochronous mode?
> usb_set_interface(stream->dev->udev, stream->intfnum, 0);
> - } else {
> - /*
> - * UVC doesn't specify how to inform a bulk-based device
> - * when the video stream is stopped. Windows sends a
> - * CLEAR_FEATURE(HALT) request to the video streaming
> - * bulk endpoint, mimic the same behaviour.
> - */
> - unsigned int epnum = stream->header.bEndpointAddress
> - & USB_ENDPOINT_NUMBER_MASK;
> - unsigned int dir = stream->header.bEndpointAddress
> - & USB_ENDPOINT_DIR_MASK;
> - unsigned int pipe;
> -
> - pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> - usb_clear_halt(stream->dev->udev, pipe);
> + return;
> }
>
> + /*
> + * UVC doesn't specify how to inform a bulk-based device
Then this comment doesn't look right. What about the code? This isn't
mentioned in the commit message either.
> + * when the video stream is stopped. Windows sends a
> + * CLEAR_FEATURE(HALT) request to the video streaming
> + * bulk endpoint, mimic the same behaviour.
> + */
> + epnum = stream->header.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
> + dir = stream->header.bEndpointAddress & USB_ENDPOINT_DIR_MASK;
> + pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir;
> + usb_clear_halt(stream->dev->udev, pipe);
> +}
> +
> +void uvc_video_stop_streaming(struct uvc_streaming *stream)
> +{
> + uvc_video_stop_transfer(stream, 1);
> +
> + /*
> + * Barrier needed to synchronize with uvc_disconnect().
> + * We cannot call usb_* functions on a disconnected USB device.
> + */
> + if (!smp_load_acquire(&stream->dev->disconnected))
> + uvc_video_halt(stream);
> +
> uvc_video_clock_cleanup(stream);
> }
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 6fb0a78b1b00..4318ce8e31db 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -559,6 +559,8 @@ struct uvc_device {
> unsigned int users;
> atomic_t nmappings;
>
> + bool disconnected;
> +
> /* Video control interface */
> #ifdef CONFIG_MEDIA_CONTROLLER
> struct media_device mdev;
>
--
Kind regards,
Sakari Ailus