On Tue, Jul 14, 2020 at 09:27:18AM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 25051b55 udc: lpc32xx: make symbol 'lpc32xx_usbddata' static > git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing > console output: https://syzkaller.appspot.com/x/log.txt?x=12e0ba00900000 > kernel config: https://syzkaller.appspot.com/x/.config?x=999be4eb2478ffa5 > dashboard link: https://syzkaller.appspot.com/bug?extid=4d3749e9612c2cfab956 > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=127354e7100000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10ba8500900000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+4d3749e9612c2cfab956@xxxxxxxxxxxxxxxxxxxxxxxxx > > mceusb 5-1:0.0: Error: urb status = -71 > mceusb 3-1:0.0: Error: urb status = -71 > mceusb 4-1:0.0: Error: urb status = -71 > mceusb 6-1:0.0: Error: urb status = -71 > mceusb 5-1:0.0: Error: urb status = -71 > rcu: INFO: rcu_sched self-detected stall on CPU This looks like an error in mceusb_dev_recv() in drivers/media/rc/mceusb.c. In the case of a -EPROTO error (indeed, any error code it doesn't recognize), the routine immediately resubmits the URB. Instead it should do the same thing as in the other error cases: return without resubmitting. (Incidentally, the calls to usb_unlink_urb() in that routine are useless and look very strange. The URB is already unlinked, since mceusb_dev_recv() is the completion handler.) Alan Stern
