* [PATCH v3 1/3] media: uvcvideo: stop stream during unregister
2024-03-25 16:31 [PATCH v3 0/3] uvcvideo: Attempt N to land UVC race conditions fixes Ricardo Ribalda
@ 2024-03-25 16:31 ` Ricardo Ribalda
2024-03-25 16:31 ` [PATCH v3 2/3] media: uvcvideo: Refactor the status irq API Ricardo Ribalda
2024-03-25 16:31 ` [PATCH v3 3/3] media: uvcvideo: Exit early if there is not int_urb Ricardo Ribalda
2 siblings, 0 replies; 8+ messages in thread
From: Ricardo Ribalda @ 2024-03-25 16:31 UTC (permalink / raw)
To: Mauro Carvalho Chehab
Cc: Guenter Roeck, Max Staudt, Tomasz Figa, Laurent Pinchart,
Alan Stern, Hans Verkuil, linux-media, linux-kernel, Sean Paul,
Ricardo Ribalda, Sakari Ailus
uvc_unregister_video() can be called asynchronously from
uvc_disconnect(). If the device is still streaming when that happens, a
plethora of race conditions can happen.
Make sure that the device has stopped streaming before exiting this
function.
If the user still holds handles to the driver's file descriptors, any
ioctl will return -ENODEV from the v4l2 core.
This change make uvc more consistent with the rest of the v4l2 drivers
using the vb2_fop_* and vb2_ioctl_* helpers.
Suggested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
drivers/media/usb/uvc/uvc_driver.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index bbd90123a4e76..17fc945c8deb6 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -1911,8 +1911,19 @@ static void uvc_unregister_video(struct uvc_device *dev)
if (!video_is_registered(&stream->vdev))
continue;
+ /*
+ * Serialize other access to the stream.
+ */
+ mutex_lock(&stream->mutex);
+ uvc_queue_streamoff(&stream->queue, stream->type);
video_unregister_device(&stream->vdev);
video_unregister_device(&stream->meta.vdev);
+ mutex_unlock(&stream->mutex);
+
+ /*
+ * Now the vdev is not streaming and all the ioctls will
+ * return -ENODEV
+ */
uvc_debugfs_cleanup_stream(stream);
}
--
2.44.0.396.g6e790dbe36-goog
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v3 2/3] media: uvcvideo: Refactor the status irq API
2024-03-25 16:31 [PATCH v3 0/3] uvcvideo: Attempt N to land UVC race conditions fixes Ricardo Ribalda
2024-03-25 16:31 ` [PATCH v3 1/3] media: uvcvideo: stop stream during unregister Ricardo Ribalda
@ 2024-03-25 16:31 ` Ricardo Ribalda
2024-03-26 8:42 ` Sergey Senozhatsky
2024-03-26 8:59 ` Sergey Senozhatsky
2024-03-25 16:31 ` [PATCH v3 3/3] media: uvcvideo: Exit early if there is not int_urb Ricardo Ribalda
2 siblings, 2 replies; 8+ messages in thread
From: Ricardo Ribalda @ 2024-03-25 16:31 UTC (permalink / raw)
To: Mauro Carvalho Chehab
Cc: Guenter Roeck, Max Staudt, Tomasz Figa, Laurent Pinchart,
Alan Stern, Hans Verkuil, linux-media, linux-kernel, Sean Paul,
Ricardo Ribalda, Sakari Ailus
There are two different use-cases of uvc_status():
- adding/removing a user when the camera is open/closed
- stopping/starting when the camera is suspended/resumed
Make the API reflect these two use-cases and move all the refcounting
and locking logic to the uvc_status.c file.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
drivers/media/usb/uvc/uvc_driver.c | 13 ++-------
drivers/media/usb/uvc/uvc_status.c | 57 ++++++++++++++++++++++++++++++++++++--
drivers/media/usb/uvc/uvc_v4l2.c | 22 ++++-----------
drivers/media/usb/uvc/uvcvideo.h | 10 ++++---
4 files changed, 68 insertions(+), 34 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 17fc945c8deb6..b579644ac0745 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2116,7 +2116,6 @@ static int uvc_probe(struct usb_interface *intf,
INIT_LIST_HEAD(&dev->streams);
kref_init(&dev->ref);
atomic_set(&dev->nmappings, 0);
- mutex_init(&dev->lock);
dev->udev = usb_get_dev(udev);
dev->intf = usb_get_intf(intf);
@@ -2282,10 +2281,7 @@ static int uvc_suspend(struct usb_interface *intf, pm_message_t message)
/* Controls are cached on the fly so they don't need to be saved. */
if (intf->cur_altsetting->desc.bInterfaceSubClass ==
UVC_SC_VIDEOCONTROL) {
- mutex_lock(&dev->lock);
- if (dev->users)
- uvc_status_stop(dev);
- mutex_unlock(&dev->lock);
+ uvc_status_suspend(dev);
return 0;
}
@@ -2316,12 +2312,7 @@ static int __uvc_resume(struct usb_interface *intf, int reset)
return ret;
}
- mutex_lock(&dev->lock);
- if (dev->users)
- ret = uvc_status_start(dev, GFP_NOIO);
- mutex_unlock(&dev->lock);
-
- return ret;
+ return uvc_status_resume(dev);
}
list_for_each_entry(stream, &dev->streams, list) {
diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index a78a88c710e24..ff66482346dde 100644
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -262,6 +262,8 @@ int uvc_status_init(struct uvc_device *dev)
uvc_input_init(dev);
+ mutex_init(&dev->status_lock);
+
dev->status = kzalloc(sizeof(*dev->status), GFP_KERNEL);
if (!dev->status)
return -ENOMEM;
@@ -292,7 +294,7 @@ int uvc_status_init(struct uvc_device *dev)
void uvc_status_unregister(struct uvc_device *dev)
{
- usb_kill_urb(dev->int_urb);
+ uvc_status_suspend(dev);
uvc_input_unregister(dev);
}
@@ -302,18 +304,22 @@ void uvc_status_cleanup(struct uvc_device *dev)
kfree(dev->status);
}
-int uvc_status_start(struct uvc_device *dev, gfp_t flags)
+static int _uvc_status_start(struct uvc_device *dev, gfp_t flags)
{
+ lockdep_assert_held(&dev->status_lock);
+
if (dev->int_urb == NULL)
return 0;
return usb_submit_urb(dev->int_urb, flags);
}
-void uvc_status_stop(struct uvc_device *dev)
+static void _uvc_status_stop(struct uvc_device *dev)
{
struct uvc_ctrl_work *w = &dev->async_ctrl;
+ lockdep_assert_held(&dev->status_lock);
+
/*
* Prevent the asynchronous control handler from requeing the URB. The
* barrier is needed so the flush_status change is visible to other
@@ -350,3 +356,48 @@ void uvc_status_stop(struct uvc_device *dev)
*/
smp_store_release(&dev->flush_status, false);
}
+
+int uvc_status_resume(struct uvc_device *dev)
+{
+ int ret = 0;
+
+ mutex_lock(&dev->status_lock);
+ if (dev->status_users)
+ ret = _uvc_status_start(dev, GFP_NOIO);
+ mutex_unlock(&dev->status_lock);
+
+ return ret;
+}
+
+void uvc_status_suspend(struct uvc_device *dev)
+{
+ mutex_lock(&dev->status_lock);
+ if (dev->status_users)
+ _uvc_status_stop(dev);
+ mutex_unlock(&dev->status_lock);
+}
+
+int uvc_status_get(struct uvc_device *dev)
+{
+ int ret = 0;
+
+ mutex_lock(&dev->status_lock);
+ if (!dev->status_users)
+ ret = _uvc_status_start(dev, GFP_KERNEL);
+ if (!ret)
+ dev->status_users++;
+ mutex_unlock(&dev->status_lock);
+
+ return ret;
+}
+
+void uvc_status_put(struct uvc_device *dev)
+{
+ mutex_lock(&dev->status_lock);
+ if (dev->status_users == 1)
+ _uvc_status_stop(dev);
+ WARN_ON(!dev->status_users);
+ if (dev->status_users)
+ dev->status_users--;
+ mutex_unlock(&dev->status_lock);
+}
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index f4988f03640ae..97c5407f66032 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -628,20 +628,13 @@ static int uvc_v4l2_open(struct file *file)
return -ENOMEM;
}
- mutex_lock(&stream->dev->lock);
- if (stream->dev->users == 0) {
- ret = uvc_status_start(stream->dev, GFP_KERNEL);
- if (ret < 0) {
- mutex_unlock(&stream->dev->lock);
- usb_autopm_put_interface(stream->dev->intf);
- kfree(handle);
- return ret;
- }
+ ret = uvc_status_get(stream->dev);
+ if (ret) {
+ usb_autopm_put_interface(stream->dev->intf);
+ kfree(handle);
+ return ret;
}
- stream->dev->users++;
- mutex_unlock(&stream->dev->lock);
-
v4l2_fh_init(&handle->vfh, &stream->vdev);
v4l2_fh_add(&handle->vfh);
handle->chain = stream->chain;
@@ -670,10 +663,7 @@ static int uvc_v4l2_release(struct file *file)
kfree(handle);
file->private_data = NULL;
- mutex_lock(&stream->dev->lock);
- if (--stream->dev->users == 0)
- uvc_status_stop(stream->dev);
- mutex_unlock(&stream->dev->lock);
+ uvc_status_put(stream->dev);
usb_autopm_put_interface(stream->dev->intf);
return 0;
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 6fb0a78b1b009..00b600eb058cc 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -555,8 +555,6 @@ struct uvc_device {
const struct uvc_device_info *info;
- struct mutex lock; /* Protects users */
- unsigned int users;
atomic_t nmappings;
/* Video control interface */
@@ -578,6 +576,8 @@ struct uvc_device {
struct usb_host_endpoint *int_ep;
struct urb *int_urb;
struct uvc_status *status;
+ struct mutex status_lock; /* Protects status_users */
+ unsigned int status_users;
bool flush_status;
struct input_dev *input;
@@ -744,8 +744,10 @@ int uvc_register_video_device(struct uvc_device *dev,
int uvc_status_init(struct uvc_device *dev);
void uvc_status_unregister(struct uvc_device *dev);
void uvc_status_cleanup(struct uvc_device *dev);
-int uvc_status_start(struct uvc_device *dev, gfp_t flags);
-void uvc_status_stop(struct uvc_device *dev);
+int uvc_status_resume(struct uvc_device *dev);
+void uvc_status_suspend(struct uvc_device *dev);
+int uvc_status_get(struct uvc_device *dev);
+void uvc_status_put(struct uvc_device *dev);
/* Controls */
extern const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited;
--
2.44.0.396.g6e790dbe36-goog
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH v3 3/3] media: uvcvideo: Exit early if there is not int_urb
2024-03-25 16:31 [PATCH v3 0/3] uvcvideo: Attempt N to land UVC race conditions fixes Ricardo Ribalda
2024-03-25 16:31 ` [PATCH v3 1/3] media: uvcvideo: stop stream during unregister Ricardo Ribalda
2024-03-25 16:31 ` [PATCH v3 2/3] media: uvcvideo: Refactor the status irq API Ricardo Ribalda
@ 2024-03-25 16:31 ` Ricardo Ribalda
2024-03-25 16:41 ` Guenter Roeck
2 siblings, 1 reply; 8+ messages in thread
From: Ricardo Ribalda @ 2024-03-25 16:31 UTC (permalink / raw)
To: Mauro Carvalho Chehab
Cc: Guenter Roeck, Max Staudt, Tomasz Figa, Laurent Pinchart,
Alan Stern, Hans Verkuil, linux-media, linux-kernel, Sean Paul,
Ricardo Ribalda, Sakari Ailus
If there is no in_urb there is no need to do a clean stop.
Also we avoid calling usb_kill_urb(NULL). It is properly handled by the
usb framework, but it is not polite.
Now that we are at it, fix the code style in uvc_status_start() for
consistency.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
drivers/media/usb/uvc/uvc_status.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index ff66482346dde..f644ac7e67427 100644
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -308,7 +308,7 @@ static int _uvc_status_start(struct uvc_device *dev, gfp_t flags)
{
lockdep_assert_held(&dev->status_lock);
- if (dev->int_urb == NULL)
+ if (!dev->int_urb)
return 0;
return usb_submit_urb(dev->int_urb, flags);
@@ -320,6 +320,9 @@ static void _uvc_status_stop(struct uvc_device *dev)
lockdep_assert_held(&dev->status_lock);
+ if (!dev->int_urb)
+ return;
+
/*
* Prevent the asynchronous control handler from requeing the URB. The
* barrier is needed so the flush_status change is visible to other
--
2.44.0.396.g6e790dbe36-goog
^ permalink raw reply related [flat|nested] 8+ messages in thread