While line6_probe() may kick off URB for a control MIDI endpoint, the
function doesn't clean up it properly at its error path. This results
in a leftover URB action that is eventually triggered later and causes
an Oops like:
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 0 Comm: swapper/1 Not tainted
RIP: 0010:usb_fill_bulk_urb ./include/linux/usb.h:1619
RIP: 0010:line6_start_listen+0x3fe/0x9e0 sound/usb/line6/driver.c:76
Call Trace:
<IRQ>
line6_data_received+0x1f7/0x470 sound/usb/line6/driver.c:326
__usb_hcd_giveback_urb+0x2e0/0x650 drivers/usb/core/hcd.c:1779
usb_hcd_giveback_urb+0x337/0x420 drivers/usb/core/hcd.c:1845
dummy_timer+0xba9/0x39f0 drivers/usb/gadget/udc/dummy_hcd.c:1965
call_timer_fn+0x2a2/0x940 kernel/time/timer.c:1281
....
Since the whole clean-up procedure is done in line6_disconnect()
callback, we can simply call it in the error path instead of
open-coding the whole again. It'll fix such an issue automagically.
The bug was spotted by syzkaller.
Fixes: eedd0e95d3 ("ALSA: line6: Don't forget to call driver's destructor at error path")
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
c95072b3d8