FAILED: patch "[PATCH] usb: gadget: uvc: fix NULL pointer dereference during unbind" failed to apply to 5.15-stable tree

index 494fdbc4e85b..8d404d88391c 100644
@@ -413,6 +413,12 @@ uvc_function_disconnect(struct uvc_device *uvc)
 {
 	int ret;
 
+	guard(mutex)(&uvc->lock);
+	if (uvc->func_unbound) {
+		dev_dbg(&uvc->vdev.dev, "skipping function deactivate (unbound)\n");
+		return;
+	}
+
 	if ((ret = usb_function_deactivate(&uvc->func)) < 0)
 		uvcg_info(&uvc->func, "UVC disconnect failed with %d\n", ret);
 }

@@ -431,6 +437,15 @@ static ssize_t function_name_show(struct device *dev,
 
 static DEVICE_ATTR_RO(function_name);
 
+static void uvc_vdev_release(struct video_device *vdev)
+{
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+
+	/* Signal uvc_function_unbind() that the video device has been released */
+	if (uvc->vdev_release_done)
+		complete(uvc->vdev_release_done);
+}
+
 static int
 uvc_register_video(struct uvc_device *uvc)
 {

@@ -443,7 +458,7 @@ uvc_register_video(struct uvc_device *uvc)
 	uvc->vdev.v4l2_dev->dev = &cdev->gadget->dev;
 	uvc->vdev.fops = &uvc_v4l2_fops;
 	uvc->vdev.ioctl_ops = &uvc_v4l2_ioctl_ops;
-	uvc->vdev.release = video_device_release_empty;
+	uvc->vdev.release = uvc_vdev_release;
 	uvc->vdev.vfl_dir = VFL_DIR_TX;
 	uvc->vdev.lock = &uvc->video.mutex;
 	uvc->vdev.device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;

@@ -659,6 +674,8 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	int ret = -EINVAL;
 
 	uvcg_info(f, "%s()\n", __func__);
+	scoped_guard(mutex, &uvc->lock)
+		uvc->func_unbound = false;
 
 	opts = fi_to_f_uvc_opts(f->fi);
 	/* Sanity check the streaming endpoint module parameters. */

@@ -988,12 +1005,19 @@ static void uvc_free(struct usb_function *f)
 static void uvc_function_unbind(struct usb_configuration *c,
 				struct usb_function *f)
 {
+	DECLARE_COMPLETION_ONSTACK(vdev_release_done);
 	struct usb_composite_dev *cdev = c->cdev;
 	struct uvc_device *uvc = to_uvc(f);
 	struct uvc_video *video = &uvc->video;
 	long wait_ret = 1;
+	bool connected;
 
 	uvcg_info(f, "%s()\n", __func__);
+	scoped_guard(mutex, &uvc->lock) {
+		uvc->func_unbound = true;
+		uvc->vdev_release_done = &vdev_release_done;
+		connected = uvc->func_connected;
+	}
 
 	kthread_cancel_work_sync(&video->hw_submit);
 

@@ -1006,7 +1030,7 @@ static void uvc_function_unbind(struct usb_configuration *c,
 	 * though the video device removal uevent. Allow some time for the
 	 * application to close out before things get deleted.
 	 */
-	if (uvc->func_connected) {
+	if (connected) {
 		uvcg_dbg(f, "waiting for clean disconnect\n");
 		wait_ret = wait_event_interruptible_timeout(uvc->func_connected_queue,
 				uvc->func_connected == false, msecs_to_jiffies(500));

@@ -1017,7 +1041,10 @@ static void uvc_function_unbind(struct usb_configuration *c,
 	video_unregister_device(&uvc->vdev);
 	v4l2_device_unregister(&uvc->v4l2_dev);
 
-	if (uvc->func_connected) {
+	scoped_guard(mutex, &uvc->lock)
+		connected = uvc->func_connected;
+
+	if (connected) {
 		/*
 		 * Wait for the release to occur to ensure there are no longer any
 		 * pending operations that may cause panics when resources are cleaned

@@ -1029,6 +1056,10 @@ static void uvc_function_unbind(struct usb_configuration *c,
 		uvcg_dbg(f, "done waiting for release with ret: %ld\n", wait_ret);
 	}
 
+	/* Wait for the video device to be released */
+	wait_for_completion(&vdev_release_done);
+	uvc->vdev_release_done = NULL;
+
 	usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
 	kfree(uvc->control_buf);
 

@@ -1047,6 +1078,8 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 		return ERR_PTR(-ENOMEM);
 
 	mutex_init(&uvc->video.mutex);
+	mutex_init(&uvc->lock);
+	uvc->func_unbound = true;
 	uvc->state = UVC_STATE_DISCONNECTED;
 	init_waitqueue_head(&uvc->func_connected_queue);
 	opts = fi_to_f_uvc_opts(fi);

index 676419a04976..7abfdd5e1eef 100644
@@ -155,6 +155,9 @@ struct uvc_device {
 	enum uvc_state state;
 	struct usb_function func;
 	struct uvc_video video;
+	struct completion *vdev_release_done;
+	struct mutex lock;	/* protects func_unbound and func_connected */
+	bool func_unbound;
 	bool func_connected;
 	wait_queue_head_t func_connected_queue;
 

index ed48d38498fb..514e5930b9ca 100644
@@ -574,6 +574,8 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
 	if (sub->type < UVC_EVENT_FIRST || sub->type > UVC_EVENT_LAST)
 		return -EINVAL;
 
+	guard(mutex)(&uvc->lock);
+
 	if (sub->type == UVC_EVENT_SETUP && uvc->func_connected)
 		return -EBUSY;
 

@@ -595,7 +597,8 @@ static void uvc_v4l2_disable(struct uvc_device *uvc)
 	uvc_function_disconnect(uvc);
 	uvcg_video_disable(&uvc->video);
 	uvcg_free_buffers(&uvc->video.queue);
-	uvc->func_connected = false;
+	scoped_guard(mutex, &uvc->lock)
+		uvc->func_connected = false;
 	wake_up_interruptible(&uvc->func_connected_queue);
 }
 

index 5df1b68e5eacc..1c07982fa5c2c 100644
@@ -393,6 +393,14 @@ uvc_function_disconnect(struct uvc_device *uvc)
 {
 	int ret;
 
+	mutex_lock(&uvc->lock);
+	if (uvc->func_unbound) {
+		dev_dbg(&uvc->vdev.dev, "skipping function deactivate (unbound)\n");
+		mutex_unlock(&uvc->lock);
+		return;
+	}
+	mutex_unlock(&uvc->lock);
+
 	if ((ret = usb_function_deactivate(&uvc->func)) < 0)
 		uvcg_info(&uvc->func, "UVC disconnect failed with %d\n", ret);
 }

@@ -411,6 +419,15 @@ static ssize_t function_name_show(struct device *dev,
 
 static DEVICE_ATTR_RO(function_name);
 
+static void uvc_vdev_release(struct video_device *vdev)
+{
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+
+	/* Signal uvc_function_unbind() that the video device has been released */
+	if (uvc->vdev_release_done)
+		complete(uvc->vdev_release_done);
+}
+
 static int
 uvc_register_video(struct uvc_device *uvc)
 {

@@ -422,7 +439,7 @@ uvc_register_video(struct uvc_device *uvc)
 	uvc->vdev.v4l2_dev->dev = &cdev->gadget->dev;
 	uvc->vdev.fops = &uvc_v4l2_fops;
 	uvc->vdev.ioctl_ops = &uvc_v4l2_ioctl_ops;
-	uvc->vdev.release = video_device_release_empty;
+	uvc->vdev.release = uvc_vdev_release;
 	uvc->vdev.vfl_dir = VFL_DIR_TX;
 	uvc->vdev.lock = &uvc->video.mutex;
 	uvc->vdev.device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;

@@ -596,6 +613,9 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
 	int ret = -EINVAL;
 
 	uvcg_info(f, "%s()\n", __func__);
+	mutex_lock(&uvc->lock);
+	uvc->func_unbound = false;
+	mutex_unlock(&uvc->lock);
 
 	opts = fi_to_f_uvc_opts(f->fi);
 	/* Sanity check the streaming endpoint module parameters.

@@ -888,18 +908,25 @@ static void uvc_free(struct usb_function *f)
 static void uvc_function_unbind(struct usb_configuration *c,
 				struct usb_function *f)
 {
+	DECLARE_COMPLETION_ONSTACK(vdev_release_done);
 	struct usb_composite_dev *cdev = c->cdev;
 	struct uvc_device *uvc = to_uvc(f);
 	long wait_ret = 1;
+	bool connected;
 
 	uvcg_info(f, "%s()\n", __func__);
+	mutex_lock(&uvc->lock);
+	uvc->func_unbound = true;
+	uvc->vdev_release_done = &vdev_release_done;
+	connected = uvc->func_connected;
+	mutex_unlock(&uvc->lock);
 
 	/* If we know we're connected via v4l2, then there should be a cleanup
 	 * of the device from userspace either via UVC_EVENT_DISCONNECT or
 	 * though the video device removal uevent. Allow some time for the
 	 * application to close out before things get deleted.
 	 */
-	if (uvc->func_connected) {
+	if (connected) {
 		uvcg_dbg(f, "waiting for clean disconnect\n");
 		wait_ret = wait_event_interruptible_timeout(uvc->func_connected_queue,
 				uvc->func_connected == false, msecs_to_jiffies(500));

@@ -910,8 +937,13 @@ static void uvc_function_unbind(struct usb_configuration *c,
 	video_unregister_device(&uvc->vdev);
 	v4l2_device_unregister(&uvc->v4l2_dev);
 
-	if (uvc->func_connected) {
-		/* Wait for the release to occur to ensure there are no longer any
+	mutex_lock(&uvc->lock);
+	connected = uvc->func_connected;
+	mutex_unlock(&uvc->lock);
+
+	if (connected) {
+		/*
+		 * Wait for the release to occur to ensure there are no longer any
 		 * pending operations that may cause panics when resources are cleaned
 		 * up.
 		 */

@@ -921,6 +953,10 @@ static void uvc_function_unbind(struct usb_configuration *c,
 		uvcg_dbg(f, "done waiting for release with ret: %ld\n", wait_ret);
 	}
 
+	/* Wait for the video device to be released */
+	wait_for_completion(&vdev_release_done);
+	uvc->vdev_release_done = NULL;
+
 	usb_ep_free_request(cdev->gadget->ep0, uvc->control_req);
 	kfree(uvc->control_buf);
 

@@ -938,6 +974,8 @@ static struct usb_function *uvc_alloc(struct usb_function_instance *fi)
 		return ERR_PTR(-ENOMEM);
 
 	mutex_init(&uvc->video.mutex);
+	mutex_init(&uvc->lock);
+	uvc->func_unbound = true;
 	uvc->state = UVC_STATE_DISCONNECTED;
 	init_waitqueue_head(&uvc->func_connected_queue);
 	opts = fi_to_f_uvc_opts(fi);

index d1a4ef74742b7..4fb751eb31726 100644
@@ -130,6 +130,9 @@ struct uvc_device {
 	enum uvc_state state;
 	struct usb_function func;
 	struct uvc_video video;
+	struct completion *vdev_release_done;
+	struct mutex lock;	/* protects func_unbound and func_connected */
+	bool func_unbound;
 	bool func_connected;
 	wait_queue_head_t func_connected_queue;
 

index 65abd55ce2348..2a1efaf3708ee 100644
@@ -234,12 +234,18 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
 	if (sub->type < UVC_EVENT_FIRST || sub->type > UVC_EVENT_LAST)
 		return -EINVAL;
 
-	if (sub->type == UVC_EVENT_SETUP && uvc->func_connected)
+	mutex_lock(&uvc->lock);
+
+	if (sub->type == UVC_EVENT_SETUP && uvc->func_connected) {
+		mutex_unlock(&uvc->lock);
 		return -EBUSY;
+	}
 
 	ret = v4l2_event_subscribe(fh, sub, 2, NULL);
-	if (ret < 0)
+	if (ret < 0) {
+		mutex_unlock(&uvc->lock);
 		return ret;
+	}
 
 	if (sub->type == UVC_EVENT_SETUP) {
 		uvc->func_connected = true;

@@ -247,6 +253,7 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
 		uvc_function_connect(uvc);
 	}
 
+	mutex_unlock(&uvc->lock);
 	return 0;
 }
 

@@ -255,7 +262,9 @@ static void uvc_v4l2_disable(struct uvc_device *uvc)
 	uvc_function_disconnect(uvc);
 	uvcg_video_enable(&uvc->video, 0);
 	uvcg_free_buffers(&uvc->video.queue);
+	mutex_lock(&uvc->lock);
 	uvc->func_connected = false;
+	mutex_unlock(&uvc->lock);
 	wake_up_interruptible(&uvc->func_connected_queue);
 }