diff mbox series

usb: iowarrior: fix deadlock on disconnect

Message ID 20190808092728.23417-1-oneukum@suse.com (mailing list archive)
State Mainlined
Commit c468a8aa790e0dfe0a7f8a39db282d39c2c00b46
Headers show
Series usb: iowarrior: fix deadlock on disconnect | expand

Commit Message

Oliver Neukum Aug. 8, 2019, 9:27 a.m. UTC 
We have to drop the mutex before we close() upon disconnect()
as close() needs the lock. This is safe to do by dropping the
mutex as intfdata is already set to NULL, so open() will fail.

Fixes: 03f36e885fc26 ("USB: open disconnect race in iowarrior")
Reported-by: syzbot+a64a382964bf6c71a9c0@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/misc/iowarrior.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index ba05dd80a020..f5bed9f29e56 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -866,19 +866,20 @@  static void iowarrior_disconnect(struct usb_interface *interface)
 	dev = usb_get_intfdata(interface);
 	mutex_lock(&iowarrior_open_disc_lock);
 	usb_set_intfdata(interface, NULL);
+	/* prevent device read, write and ioctl */
+	dev->present = 0;
 
 	minor = dev->minor;
+	mutex_unlock(&iowarrior_open_disc_lock);
+	/* give back our minor - this will call close() locks need to be dropped at this point*/
 
-	/* give back our minor */
 	usb_deregister_dev(interface, &iowarrior_class);
 
 	mutex_lock(&dev->mutex);
 
 	/* prevent device read, write and ioctl */
-	dev->present = 0;
 
 	mutex_unlock(&dev->mutex);
-	mutex_unlock(&iowarrior_open_disc_lock);
 
 	if (dev->opened) {
 		/* There is a process that holds a filedescriptor to the device ,