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usb: iowarrior: fix deadlock on disconnect

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commit c468a8aa790e0dfe0a7f8a39db282d39c2c00b46 upstream.

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: 03f36e885f ("USB: open disconnect race in iowarrior")
Reported-by: syzbot+a64a382964bf6c71a9c0@syzkaller.appspotmail.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20190808092728.23417-1-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oliver Neukum 2019-08-08 11:27:28 +02:00 • committed by Greg Kroah-Hartman
parent 3904234bd0
commit 334bcf6f25
1 changed files with 4 additions and 3 deletions
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7
drivers/usb/misc/iowarrior.c
View file

@ -898,19 +898,20 @@ 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 ,