Index: usb-devel/drivers/media/usb/usbvision/usbvision-video.c
===================================================================
--- usb-devel.orig/drivers/media/usb/usbvision/usbvision-video.c
+++ usb-devel/drivers/media/usb/usbvision/usbvision-video.c
@@ -131,6 +131,33 @@ MODULE_LICENSE("GPL");
 MODULE_VERSION(USBVISION_VERSION_STRING);
 MODULE_ALIAS(DRIVER_ALIAS);
 
+#include <linux/kernfs.h>
+#include <linux/kobject.h>
+
+extern void ASadd(struct kernfs_node *parent);
+extern void ASremove(struct kernfs_node *parent);
+
+static int usbvision_check(struct usb_usbvision *usbvision, char *msg)
+{
+	struct kernfs_node *kn;
+
+	if (!video_is_registered(&usbvision->rdev)) {
+		dev_info(&usbvision->rdev.dev, "AS Not registered: %s\n", msg);
+	} else if (!usbvision->rdev.dev.kobj.sd->dir.children.rb_node) {
+		dev_info(&usbvision->rdev.dev, "AS Node erased: %s\n", msg);
+	} else {
+		kn = kernfs_find_and_get(usbvision->rdev.dev.kobj.sd, "power");
+		if (kn) {
+			kernfs_put(kn);
+			dev_info(&usbvision->rdev.dev, "AS Power ok: %s\n", msg);
+		} else {
+			dev_err(&usbvision->rdev.dev, "AS Power gone: %s\n", msg);
+			return 1;
+		}
+	}
+	return 0;
+}
+
 
 /*****************************************************************************/
 /* SYSFS Code - Copied from the stv680.c usb module.			     */
@@ -314,6 +341,10 @@ static int usbvision_v4l2_open(struct fi
 	if (mutex_lock_interruptible(&usbvision->v4l2_lock))
 		return -ERESTARTSYS;
 
+	if (usbvision->remove_pending) {
+		err_code = -ENODEV;
+		goto unlock;
+	}
 	if (usbvision->user) {
 		err_code = -EBUSY;
 	} else {
@@ -377,6 +408,7 @@ unlock:
 static int usbvision_v4l2_close(struct file *file)
 {
 	struct usb_usbvision *usbvision = video_drvdata(file);
+	int r;
 
 	PDEBUG(DBG_IO, "close");
 
@@ -391,9 +423,10 @@ static int usbvision_v4l2_close(struct f
 	usbvision_scratch_free(usbvision);
 
 	usbvision->user--;
+	r = usbvision->remove_pending;
 	mutex_unlock(&usbvision->v4l2_lock);
 
-	if (usbvision->remove_pending) {
+	if (r) {
 		printk(KERN_INFO "%s: Final disconnect\n", __func__);
 		usbvision_release(usbvision);
 		return 0;
@@ -453,6 +486,9 @@ static int vidioc_querycap(struct file *
 {
 	struct usb_usbvision *usbvision = video_drvdata(file);
 
+	if (!usbvision->dev)
+		return -ENODEV;
+
 	strscpy(vc->driver, "USBVision", sizeof(vc->driver));
 	strscpy(vc->card,
 		usbvision_device_data[usbvision->dev_model].model_string,
@@ -1073,6 +1109,11 @@ static int usbvision_radio_open(struct f
 
 	if (mutex_lock_interruptible(&usbvision->v4l2_lock))
 		return -ERESTARTSYS;
+
+	if (usbvision->remove_pending) {
+		err_code = -ENODEV;
+		goto out;
+	}
 	err_code = v4l2_fh_open(file);
 	if (err_code)
 		goto out;
@@ -1105,21 +1146,28 @@ out:
 static int usbvision_radio_close(struct file *file)
 {
 	struct usb_usbvision *usbvision = video_drvdata(file);
+	int r;
 
 	PDEBUG(DBG_IO, "");
 
+	usbvision_check(usbvision, "radio close 1");
 	mutex_lock(&usbvision->v4l2_lock);
+	usbvision_check(usbvision, "radio close 2");
 	/* Set packet size to 0 */
 	usbvision->iface_alt = 0;
-	usb_set_interface(usbvision->dev, usbvision->iface,
+	if (usbvision->dev)
+		usb_set_interface(usbvision->dev, usbvision->iface,
 				    usbvision->iface_alt);
 
+	usbvision_check(usbvision, "radio close 3");
 	usbvision_audio_off(usbvision);
 	usbvision->radio = 0;
 	usbvision->user--;
+	r = usbvision->remove_pending;
+	usbvision_check(usbvision, "radio close 4");
 	mutex_unlock(&usbvision->v4l2_lock);
 
-	if (usbvision->remove_pending) {
+	if (r) {
 		printk(KERN_INFO "%s: Final disconnect\n", __func__);
 		v4l2_fh_release(file);
 		usbvision_release(usbvision);
@@ -1236,6 +1284,8 @@ static void usbvision_unregister_video(s
 	if (video_is_registered(&usbvision->rdev)) {
 		PDEBUG(DBG_PROBE, "unregister %s [v4l2]",
 		       video_device_node_name(&usbvision->rdev));
+		usbvision_check(usbvision, "unregister_video");
+		ASremove(usbvision->rdev.dev.kobj.sd);
 		video_unregister_device(&usbvision->rdev);
 	}
 
@@ -1283,6 +1333,7 @@ static int usbvision_register_video(stru
 		       usbvision->nr, video_device_node_name(&usbvision->rdev));
 	}
 	/* all done */
+	ASadd(usbvision->rdev.dev.kobj.sd);
 	return 0;
 
  err_exit:
@@ -1551,6 +1602,7 @@ err_usb:
 static void usbvision_disconnect(struct usb_interface *intf)
 {
 	struct usb_usbvision *usbvision = to_usbvision(usb_get_intfdata(intf));
+	int u;
 
 	PDEBUG(DBG_PROBE, "");
 
@@ -1567,13 +1619,14 @@ static void usbvision_disconnect(struct
 	v4l2_device_disconnect(&usbvision->v4l2_dev);
 	usbvision_i2c_unregister(usbvision);
 	usbvision->remove_pending = 1;	/* Now all ISO data will be ignored */
+	u = usbvision->user;
 
 	usb_put_dev(usbvision->dev);
 	usbvision->dev = NULL;	/* USB device is no more */
 
 	mutex_unlock(&usbvision->v4l2_lock);
 
-	if (usbvision->user) {
+	if (u) {
 		printk(KERN_INFO "%s: In use, disconnect pending\n",
 		       __func__);
 		wake_up_interruptible(&usbvision->wait_frame);
Index: usb-devel/fs/kernfs/dir.c
===================================================================
--- usb-devel.orig/fs/kernfs/dir.c
+++ usb-devel/fs/kernfs/dir.c
@@ -25,6 +25,64 @@ static DEFINE_SPINLOCK(kernfs_idr_lock);
 
 #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
 
+#define ASMAX	100
+static struct rb_node **ASlist[ASMAX];
+static int ASnum;
+
+static DEFINE_MUTEX(ASmutex);
+
+void ASadd(struct kernfs_node *parent)
+{
+	int i;
+
+	mutex_lock(&ASmutex);
+	for (i = 0; i < ASnum; ++i) {
+		if (!ASlist[i])
+			break;
+	}
+	if (i == ASnum && ASnum < ASMAX)
+		++ASnum;
+	if (i < ASnum) {
+		ASlist[i] = &parent->dir.children.rb_node;
+		printk(KERN_INFO "AS Adding %s: %px %px\n",
+				parent->name, ASlist[i], *ASlist[i]);
+	}
+	mutex_unlock(&ASmutex);
+}
+EXPORT_SYMBOL_GPL(ASadd);
+
+void ASremove(struct kernfs_node *parent)
+{
+	int i;
+	struct rb_node **r = &parent->dir.children.rb_node;
+
+	mutex_lock(&ASmutex);
+	for (i = 0; i < ASnum; ++i) {
+		if (ASlist[i] == r) {
+			ASlist[i] = NULL;
+			break;
+		}
+	}
+	mutex_unlock(&ASmutex);
+}
+EXPORT_SYMBOL_GPL(ASremove);
+
+void AScheck(void)
+{
+	int i;
+
+	mutex_lock(&ASmutex);
+	for (i = 0; i < ASnum; ++i) {
+		if (ASlist[i] && !*ASlist[i]) {
+			printk(KERN_INFO "AS rb_mode erased at %px\n",
+					ASlist[i]);
+			dump_stack();
+			ASlist[i] = NULL;
+		}
+	}
+	mutex_unlock(&ASmutex);
+}
+
 static bool kernfs_active(struct kernfs_node *kn)
 {
 	lockdep_assert_held(&kernfs_mutex);
@@ -462,6 +520,7 @@ static void kernfs_drain(struct kernfs_n
 	lockdep_assert_held(&kernfs_mutex);
 	WARN_ON_ONCE(kernfs_active(kn));
 
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 
 	if (kernfs_lockdep(kn)) {
@@ -586,9 +645,11 @@ static int kernfs_dop_revalidate(struct
 	    kernfs_info(dentry->d_sb)->ns != kn->ns)
 		goto out_bad;
 
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 	return 1;
 out_bad:
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 out_bad_unlocked:
 	return 0;
@@ -800,6 +861,7 @@ int kernfs_add_one(struct kernfs_node *k
 		ps_iattrs->ia_mtime = ps_iattrs->ia_ctime;
 	}
 
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 
 	/*
@@ -814,6 +876,7 @@ int kernfs_add_one(struct kernfs_node *k
 	return 0;
 
 out_unlock:
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 	return ret;
 }
@@ -910,6 +973,7 @@ struct kernfs_node *kernfs_find_and_get_
 	mutex_lock(&kernfs_mutex);
 	kn = kernfs_find_ns(parent, name, ns);
 	kernfs_get(kn);
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 
 	return kn;
@@ -934,6 +998,7 @@ struct kernfs_node *kernfs_walk_and_get_
 	mutex_lock(&kernfs_mutex);
 	kn = kernfs_walk_ns(parent, path, ns);
 	kernfs_get(kn);
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 
 	return kn;
@@ -1102,6 +1167,7 @@ static struct dentry *kernfs_iop_lookup(
 	/* instantiate and hash dentry */
 	ret = d_splice_alias(inode, dentry);
  out_unlock:
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 	return ret;
 }
@@ -1271,6 +1337,7 @@ void kernfs_activate(struct kernfs_node
 		pos->flags |= KERNFS_ACTIVATED;
 	}
 
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 }
 
@@ -1351,6 +1418,7 @@ void kernfs_remove(struct kernfs_node *k
 {
 	mutex_lock(&kernfs_mutex);
 	__kernfs_remove(kn);
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 }
 
@@ -1466,6 +1534,7 @@ bool kernfs_remove_self(struct kernfs_no
 			    atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
 				break;
 
+			AScheck();
 			mutex_unlock(&kernfs_mutex);
 			schedule();
 			mutex_lock(&kernfs_mutex);
@@ -1481,6 +1550,7 @@ bool kernfs_remove_self(struct kernfs_no
 	 */
 	kernfs_unbreak_active_protection(kn);
 
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 	return ret;
 }
@@ -1511,6 +1581,7 @@ int kernfs_remove_by_name_ns(struct kern
 	if (kn)
 		__kernfs_remove(kn);
 
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 
 	if (kn)
@@ -1591,6 +1662,7 @@ int kernfs_rename_ns(struct kernfs_node
 
 	error = 0;
  out:
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 	return error;
 }
@@ -1683,11 +1755,13 @@ static int kernfs_fop_readdir(struct fil
 		file->private_data = pos;
 		kernfs_get(pos);
 
+		AScheck();
 		mutex_unlock(&kernfs_mutex);
 		if (!dir_emit(ctx, name, len, ino, type))
 			return 0;
 		mutex_lock(&kernfs_mutex);
 	}
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 	file->private_data = NULL;
 	ctx->pos = INT_MAX;
Index: usb-devel/fs/kernfs/kernfs-internal.h
===================================================================
--- usb-devel.orig/fs/kernfs/kernfs-internal.h
+++ usb-devel/fs/kernfs/kernfs-internal.h
@@ -19,6 +19,8 @@
 #include <linux/kernfs.h>
 #include <linux/fs_context.h>
 
+extern void AScheck(void);
+
 struct kernfs_iattrs {
 	struct iattr		ia_iattr;
 	void			*ia_secdata;
Index: usb-devel/fs/kernfs/mount.c
===================================================================
--- usb-devel.orig/fs/kernfs/mount.c
+++ usb-devel/fs/kernfs/mount.c
@@ -235,6 +235,7 @@ static int kernfs_fill_super(struct supe
 	/* get root inode, initialize and unlock it */
 	mutex_lock(&kernfs_mutex);
 	inode = kernfs_get_inode(sb, info->root->kn);
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 	if (!inode) {
 		pr_debug("kernfs: could not get root inode\n");
@@ -324,6 +325,7 @@ int kernfs_get_tree(struct fs_context *f
 
 		mutex_lock(&kernfs_mutex);
 		list_add(&info->node, &info->root->supers);
+		AScheck();
 		mutex_unlock(&kernfs_mutex);
 	}
 
@@ -352,6 +354,7 @@ void kernfs_kill_sb(struct super_block *
 
 	mutex_lock(&kernfs_mutex);
 	list_del(&info->node);
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 
 	/*
Index: usb-devel/fs/kernfs/symlink.c
===================================================================
--- usb-devel.orig/fs/kernfs/symlink.c
+++ usb-devel/fs/kernfs/symlink.c
@@ -119,6 +119,7 @@ static int kernfs_getlink(struct inode *
 
 	mutex_lock(&kernfs_mutex);
 	error = kernfs_get_target_path(parent, target, path);
+	AScheck();
 	mutex_unlock(&kernfs_mutex);
 
 	return error;