FAILED: patch "[PATCH] USB: iowarrior: fix use-after-free on disconnect race" failed to apply to 5.10-stable tree

index 88c6d1d1da11..de2b236ef903 100644
@@ -72,6 +72,7 @@ static struct usb_driver iowarrior_driver;
 
 /* Structure to hold all of our device specific stuff */
 struct iowarrior {
+	struct kref kref;
 	struct mutex mutex;			/* locks this structure */
 	struct usb_device *udev;		/* save off the usb device pointer */
 	struct usb_interface *interface;	/* the interface for this device */

@@ -240,8 +241,10 @@ static void iowarrior_write_callback(struct urb *urb)
 /*
  *	iowarrior_delete
  */
-static inline void iowarrior_delete(struct iowarrior *dev)
+static inline void iowarrior_delete(struct kref *kref)
 {
+	struct iowarrior *dev = container_of(kref, struct iowarrior, kref);
+
 	kfree(dev->int_in_buffer);
 	usb_free_urb(dev->int_in_urb);
 	kfree(dev->read_queue);

@@ -637,6 +640,9 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 	}
 	/* increment our usage count for the driver */
 	++dev->opened;
+
+	kref_get(&dev->kref);
+
 	/* save our object in the file's private structure */
 	file->private_data = dev;
 	retval = 0;

@@ -652,7 +658,6 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 static int iowarrior_release(struct inode *inode, struct file *file)
 {
 	struct iowarrior *dev;
-	int retval = 0;
 
 	dev = file->private_data;
 	if (!dev)

@@ -660,29 +665,18 @@ static int iowarrior_release(struct inode *inode, struct file *file)
 
 	/* lock our device */
 	mutex_lock(&dev->mutex);
+	dev->opened = 0;	/* we're closing now */
 
-	if (dev->opened <= 0) {
-		retval = -ENODEV;	/* close called more than once */
-		mutex_unlock(&dev->mutex);
-	} else {
-		dev->opened = 0;	/* we're closing now */
-		retval = 0;
-		if (dev->present) {
-			/*
-			   The device is still connected so we only shutdown
-			   pending read-/write-ops.
-			 */
-			usb_kill_urb(dev->int_in_urb);
-			wake_up_interruptible(&dev->read_wait);
-			wake_up_interruptible(&dev->write_wait);
-			mutex_unlock(&dev->mutex);
-		} else {
-			/* The device was unplugged, cleanup resources */
-			mutex_unlock(&dev->mutex);
-			iowarrior_delete(dev);
-		}
+	if (dev->present) {
+		usb_kill_urb(dev->int_in_urb);
+		wake_up_interruptible(&dev->read_wait);
+		wake_up_interruptible(&dev->write_wait);
 	}
-	return retval;
+	mutex_unlock(&dev->mutex);
+
+	kref_put(&dev->kref, iowarrior_delete);
+
+	return 0;
 }
 
 static __poll_t iowarrior_poll(struct file *file, poll_table * wait)

@@ -767,6 +761,7 @@ static int iowarrior_probe(struct usb_interface *interface,
 	if (!dev)
 		return retval;
 
+	kref_init(&dev->kref);
 	mutex_init(&dev->mutex);
 
 	atomic_set(&dev->intr_idx, 0);

@@ -885,7 +880,8 @@ static int iowarrior_probe(struct usb_interface *interface,
 	return retval;
 
 error:
-	iowarrior_delete(dev);
+	kref_put(&dev->kref, iowarrior_delete);
+
 	return retval;
 }
 

@@ -909,19 +905,14 @@ static void iowarrior_disconnect(struct usb_interface *interface)
 	usb_kill_anchored_urbs(&dev->submitted);
 
 	if (dev->opened) {
-		/* There is a process that holds a filedescriptor to the device ,
-		   so we only shutdown read-/write-ops going on.
-		   Deleting the device is postponed until close() was called.
-		 */
 		usb_kill_urb(dev->int_in_urb);
 		wake_up_interruptible(&dev->read_wait);
 		wake_up_interruptible(&dev->write_wait);
-		mutex_unlock(&dev->mutex);
-	} else {
-		/* no process is using the device, cleanup now */
-		mutex_unlock(&dev->mutex);
-		iowarrior_delete(dev);
 	}
+
+	mutex_unlock(&dev->mutex);
+
+	kref_put(&dev->kref, iowarrior_delete);
 }
 
 /* usb specific object needed to register this driver with the usb subsystem */

index 2a0036d8fc2926..7c217b1f71f293 100644
@@ -74,7 +74,6 @@ struct iowarrior {
 	struct mutex mutex;			/* locks this structure */
 	struct usb_device *udev;		/* save off the usb device pointer */
 	struct usb_interface *interface;	/* the interface for this device */
-	unsigned char minor;			/* the starting minor number for this device */
 	struct usb_endpoint_descriptor *int_out_endpoint;	/* endpoint for reading (needed for IOW56 only) */
 	struct usb_endpoint_descriptor *int_in_endpoint;	/* endpoint for reading */
 	struct urb *int_in_urb;		/* the urb for reading data */

@@ -246,7 +245,6 @@ static void iowarrior_write_callback(struct urb *urb)
  */
 static inline void iowarrior_delete(struct iowarrior *dev)
 {
-	dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
 	kfree(dev->int_in_buffer);
 	usb_free_urb(dev->int_in_urb);
 	kfree(dev->read_queue);

@@ -297,9 +295,6 @@ static ssize_t iowarrior_read(struct file *file, char __user *buffer,
 		goto exit;
 	}
 
-	dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
-		dev->minor, count);
-
 	/* read count must be packet size (+ time stamp) */
 	if ((count != dev->report_size)
 	    && (count != (dev->report_size + 1))) {

@@ -379,8 +374,6 @@ static ssize_t iowarrior_write(struct file *file,
 		retval = -ENODEV;
 		goto exit;
 	}
-	dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n",
-		dev->minor, count);
 	/* if count is 0 we're already done */
 	if (count == 0) {
 		retval = 0;

@@ -526,9 +519,6 @@ static long iowarrior_ioctl(struct file *file, unsigned int cmd,
 		goto error_out;
 	}
 
-	dev_dbg(&dev->interface->dev, "minor %d, cmd 0x%.4x, arg %ld\n",
-		dev->minor, cmd, arg);
-
 	retval = 0;
 	io_res = 0;
 	switch (cmd) {

@@ -675,8 +665,6 @@ static int iowarrior_release(struct inode *inode, struct file *file)
 	if (!dev)
 		return -ENODEV;
 
-	dev_dbg(&dev->interface->dev, "minor %d\n", dev->minor);
-
 	/* lock our device */
 	mutex_lock(&dev->mutex);
 

@@ -779,6 +767,7 @@ static int iowarrior_probe(struct usb_interface *interface,
 	struct usb_host_interface *iface_desc;
 	int retval = -ENOMEM;
 	int res;
+	int minor;
 
 	/* allocate memory for our device state and initialize it */
 	dev = kzalloc(sizeof(struct iowarrior), GFP_KERNEL);

@@ -894,12 +883,12 @@ static int iowarrior_probe(struct usb_interface *interface,
 		goto error;
 	}
 
-	dev->minor = interface->minor;
+	minor = interface->minor;
 
 	/* let the user know what node this device is now attached to */
 	dev_info(&interface->dev, "IOWarrior product=0x%x, serial=%s interface=%d "
 		 "now attached to iowarrior%d\n", dev->product_id, dev->chip_serial,
-		 iface_desc->desc.bInterfaceNumber, dev->minor - IOWARRIOR_MINOR_BASE);
+		 iface_desc->desc.bInterfaceNumber, minor - IOWARRIOR_MINOR_BASE);
 	return retval;
 
 error:

index 7c217b1f71f293..d23cb584c13c39 100644
@@ -71,6 +71,7 @@ static struct usb_driver iowarrior_driver;
 
 /* Structure to hold all of our device specific stuff */
 struct iowarrior {
+	struct kref kref;
 	struct mutex mutex;			/* locks this structure */
 	struct usb_device *udev;		/* save off the usb device pointer */
 	struct usb_interface *interface;	/* the interface for this device */

@@ -243,8 +244,10 @@ static void iowarrior_write_callback(struct urb *urb)
 /*
  *	iowarrior_delete
  */
-static inline void iowarrior_delete(struct iowarrior *dev)
+static inline void iowarrior_delete(struct kref *kref)
 {
+	struct iowarrior *dev = container_of(kref, struct iowarrior, kref);
+
 	kfree(dev->int_in_buffer);
 	usb_free_urb(dev->int_in_urb);
 	kfree(dev->read_queue);

@@ -644,6 +647,9 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 	}
 	/* increment our usage count for the driver */
 	++dev->opened;
+
+	kref_get(&dev->kref);
+
 	/* save our object in the file's private structure */
 	file->private_data = dev;
 	retval = 0;

@@ -659,7 +665,6 @@ static int iowarrior_open(struct inode *inode, struct file *file)
 static int iowarrior_release(struct inode *inode, struct file *file)
 {
 	struct iowarrior *dev;
-	int retval = 0;
 
 	dev = file->private_data;
 	if (!dev)

@@ -667,29 +672,18 @@ static int iowarrior_release(struct inode *inode, struct file *file)
 
 	/* lock our device */
 	mutex_lock(&dev->mutex);
+	dev->opened = 0;	/* we're closing now */
 
-	if (dev->opened <= 0) {
-		retval = -ENODEV;	/* close called more than once */
-		mutex_unlock(&dev->mutex);
-	} else {
-		dev->opened = 0;	/* we're closing now */
-		retval = 0;
-		if (dev->present) {
-			/*
-			   The device is still connected so we only shutdown
-			   pending read-/write-ops.
-			 */
-			usb_kill_urb(dev->int_in_urb);
-			wake_up_interruptible(&dev->read_wait);
-			wake_up_interruptible(&dev->write_wait);
-			mutex_unlock(&dev->mutex);
-		} else {
-			/* The device was unplugged, cleanup resources */
-			mutex_unlock(&dev->mutex);
-			iowarrior_delete(dev);
-		}
+	if (dev->present) {
+		usb_kill_urb(dev->int_in_urb);
+		wake_up_interruptible(&dev->read_wait);
+		wake_up_interruptible(&dev->write_wait);
 	}
-	return retval;
+	mutex_unlock(&dev->mutex);
+
+	kref_put(&dev->kref, iowarrior_delete);
+
+	return 0;
 }
 
 static __poll_t iowarrior_poll(struct file *file, poll_table * wait)

@@ -774,6 +768,7 @@ static int iowarrior_probe(struct usb_interface *interface,
 	if (!dev)
 		return retval;
 
+	kref_init(&dev->kref);
 	mutex_init(&dev->mutex);
 
 	atomic_set(&dev->intr_idx, 0);

@@ -892,7 +887,8 @@ static int iowarrior_probe(struct usb_interface *interface,
 	return retval;
 
 error:
-	iowarrior_delete(dev);
+	kref_put(&dev->kref, iowarrior_delete);
+
 	return retval;
 }
 

@@ -913,20 +909,15 @@ static void iowarrior_disconnect(struct usb_interface *interface)
 	dev->present = 0;
 
 	if (dev->opened) {
-		/* There is a process that holds a filedescriptor to the device ,
-		   so we only shutdown read-/write-ops going on.
-		   Deleting the device is postponed until close() was called.
-		 */
 		usb_kill_urb(dev->int_in_urb);
 		usb_kill_anchored_urbs(&dev->submitted);
 		wake_up_interruptible(&dev->read_wait);
 		wake_up_interruptible(&dev->write_wait);
-		mutex_unlock(&dev->mutex);
-	} else {
-		/* no process is using the device, cleanup now */
-		mutex_unlock(&dev->mutex);
-		iowarrior_delete(dev);
 	}
+
+	mutex_unlock(&dev->mutex);
+
+	kref_put(&dev->kref, iowarrior_delete);
 }
 
 /* usb specific object needed to register this driver with the usb subsystem */