USB: fix locking in idmouse
Pete caused me to lock at buggy drivers in this respect. The idmouse has a race between open and disconnect. This patch - solves the open/disconnect race - switches locking to mutexes Signed-off-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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parent
439a903a96
commit
54d2bc068f
1 changed files with 28 additions and 17 deletions
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@ -66,6 +66,7 @@ static struct usb_device_id idmouse_table[] = {
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USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT, value, index, NULL, 0, 1000)
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MODULE_DEVICE_TABLE(usb, idmouse_table);
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static DEFINE_MUTEX(open_disc_mutex);
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/* structure to hold all of our device specific stuff */
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struct usb_idmouse {
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@ -80,7 +81,7 @@ struct usb_idmouse {
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int open; /* if the port is open or not */
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int present; /* if the device is not disconnected */
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struct semaphore sem; /* locks this structure */
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struct mutex lock; /* locks this structure */
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};
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@ -213,13 +214,17 @@ static int idmouse_open(struct inode *inode, struct file *file)
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if (!interface)
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return -ENODEV;
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mutex_lock(&open_disc_mutex);
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/* get the device information block from the interface */
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dev = usb_get_intfdata(interface);
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if (!dev)
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if (!dev) {
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mutex_unlock(&open_disc_mutex);
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return -ENODEV;
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}
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/* lock this device */
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down(&dev->sem);
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mutex_lock(&dev->lock);
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mutex_unlock(&open_disc_mutex);
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/* check if already open */
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if (dev->open) {
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@ -245,7 +250,7 @@ static int idmouse_open(struct inode *inode, struct file *file)
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error:
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/* unlock this device */
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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return result;
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}
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@ -258,12 +263,14 @@ static int idmouse_release(struct inode *inode, struct file *file)
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if (dev == NULL)
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return -ENODEV;
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mutex_lock(&open_disc_mutex);
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/* lock our device */
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down(&dev->sem);
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mutex_lock(&dev->lock);
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/* are we really open? */
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if (dev->open <= 0) {
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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mutex_unlock(&open_disc_mutex);
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return -ENODEV;
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}
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@ -271,10 +278,12 @@ static int idmouse_release(struct inode *inode, struct file *file)
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if (!dev->present) {
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/* the device was unplugged before the file was released */
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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mutex_unlock(&open_disc_mutex);
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idmouse_delete(dev);
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} else {
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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mutex_unlock(&open_disc_mutex);
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}
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return 0;
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}
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@ -286,18 +295,18 @@ static ssize_t idmouse_read(struct file *file, char __user *buffer, size_t count
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int result;
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/* lock this object */
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down(&dev->sem);
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mutex_lock(&dev->lock);
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/* verify that the device wasn't unplugged */
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if (!dev->present) {
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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return -ENODEV;
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}
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result = simple_read_from_buffer(buffer, count, ppos,
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dev->bulk_in_buffer, IMGSIZE);
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/* unlock the device */
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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return result;
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}
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@ -320,7 +329,7 @@ static int idmouse_probe(struct usb_interface *interface,
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if (dev == NULL)
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return -ENOMEM;
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init_MUTEX(&dev->sem);
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mutex_init(&dev->lock);
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dev->udev = udev;
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dev->interface = interface;
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@ -372,24 +381,26 @@ static void idmouse_disconnect(struct usb_interface *interface)
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/* get device structure */
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dev = usb_get_intfdata(interface);
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usb_set_intfdata(interface, NULL);
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/* give back our minor */
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usb_deregister_dev(interface, &idmouse_class);
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/* lock it */
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down(&dev->sem);
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mutex_lock(&open_disc_mutex);
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usb_set_intfdata(interface, NULL);
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/* lock the device */
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mutex_lock(&dev->lock);
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mutex_unlock(&open_disc_mutex);
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/* prevent device read, write and ioctl */
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dev->present = 0;
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/* if the device is opened, idmouse_release will clean this up */
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if (!dev->open) {
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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idmouse_delete(dev);
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} else {
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/* unlock */
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up(&dev->sem);
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mutex_unlock(&dev->lock);
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}
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info("%s disconnected", DRIVER_DESC);
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