On Mon, Sep 23, 2019 at 05:41:54PM +0800, Peter Chen wrote: > > On Tue, Jul 9, 2019 at 2:27 PM syzbot > > <syzbot+58e201002fe1e775e1ae@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > Hello, > > > > > > syzbot found the following crash on: > > > > > > HEAD commit: 7829a896 usb-fuzzer: main usb gadget fuzzer driver > > > git tree: https://github.com/google/kasan.git usb-fuzzer > > > console output: https://syzkaller.appspot.com/x/log.txt?x=118d136da00000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=f6d4561982f71f63 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=58e201002fe1e775e1ae > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > Reported-by: syzbot+58e201002fe1e775e1ae@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > > > dummy_hcd dummy_hcd.5: no ep configured for urb 00000000c6093b7b > > > xpad 6-1:0.169: xpad_irq_out - usb_submit_urb failed with result -19 > > > ================================================================== > > > BUG: KASAN: use-after-free in debug_spin_lock_before > > > kernel/locking/spinlock_debug.c:83 [inline] > > > BUG: KASAN: use-after-free in do_raw_spin_lock+0x24d/0x280 > > > kernel/locking/spinlock_debug.c:112 > > > Read of size 4 at addr ffff8881d0e584dc by task kworker/1:4/2786 > > > > > It should due to URB is freed at xpad_disconnect, but xpad_irq_out > still tries to access > freed URB. > > Peter > > #syz test: https://github.com/google/kasan.git 7829a896 > > diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c > index 6b40a1c68f9f..32b7a199b580 100644 > --- a/drivers/input/joystick/xpad.c > +++ b/drivers/input/joystick/xpad.c > @@ -1850,6 +1850,7 @@ static void xpad_disconnect(struct usb_interface *intf) > > xpad_deinit_input(xpad); > > + usb_kill_urb(xpad->irq_out); I'm not sure this is the right fix. The interrupt-urb should have been stopped by xpad_stop_output() just above. Perhaps the type test in that function is broken, or we may have a race where another thread is submitting the URB after we tried to stop it which we fail to handle. Didn't check that closely, though. Johan
