From c468a8aa790e0dfe0a7f8a39db282d39c2c00b46 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Thu, 8 Aug 2019 11:27:28 +0200 Subject: [PATCH] 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 --- drivers/usb/misc/iowarrior.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c index ba05dd8..f5bed9f 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 , -- 2.7.4