From: Oliver Neukum Date: Thu, 8 Aug 2019 09:27:28 +0000 (+0200) Subject: usb: iowarrior: fix deadlock on disconnect X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=c468a8aa790e0dfe0a7f8a39db282d39c2c00b46;p=openwrt%2Fstaging%2Fblogic.git usb: iowarrior: fix deadlock on disconnect 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 Cc: stable Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20190808092728.23417-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman --- 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 ,