On Tue, 23 Apr 2019, Andrey Konovalov wrote: > > This original bug report included a "USB disconnect" line, as shown > > above. The newer results, for runs with my patches added, do not. At > > least, if such a line was present, it didn't show up in the console > > output files -- the most recent one contains nothing but repeats of > > that "yurex_interrupt - unknown status received: -71" line, although > > for devices on multiple buses. > > > > Is there any way to get more information about what's happening, such > > as a complete kernel log? > > It should be possible to provide the full log for the result of the > "syz test" command. I'll talk to Dmitry about this when he's back from > vacation next week. > > > And perhaps to run the test with just a > > single dummy-hcd bus instead of 6? > > Hm, it might be possible to implement overriding of syz-execprog flags > and provide them via "syz test". It's not implemented right now > though. > > Running the reproducer manually is the most flexible way to make > changes to the way it's ran or to make changes to the environment. In > this case I haven't managed to reproduce the hang manually though :( > > I see two ways to deal with this right now: > > 1. Submit your fix (it fixes the original issue for me) and wait until > it gets into the usb-fuzzer tree. Then maybe syzbot will report the > hang and provide a better reproducer. > > 2. Change the testing patch to also suppress those "yurex_interrupt - > unknown status received: -71" messages and rerun the "syz test" > command. Hopefully then syzbot will provide the full kernel log. That's a great suggestion! Here's the next attempt. Alan Stern #syz test: https://github.com/google/kasan.git usb-fuzzer --- a/drivers/usb/misc/yurex.c +++ b/drivers/usb/misc/yurex.c @@ -143,8 +143,10 @@ static void yurex_interrupt(struct urb * /* The device is terminated, clean up */ return; default: +#if 0 dev_err(&dev->interface->dev, "%s - unknown status received: %d\n", __func__, status); +#endif goto exit; } @@ -178,6 +180,10 @@ static void yurex_interrupt(struct urb * } exit: + if (!usb_get_intfdata(dev->interface)) { + dev_info(&dev->interface->dev, "%s unbound\n", __func__); + return; + } retval = usb_submit_urb(dev->urb, GFP_ATOMIC); if (retval) { dev_err(&dev->interface->dev, "%s - usb_submit_urb failed: %d\n", @@ -309,11 +315,15 @@ static void yurex_disconnect(struct usb_ dev = usb_get_intfdata(interface); usb_set_intfdata(interface, NULL); + dev_info(&interface->dev, "%s\n", __func__); /* give back our minor */ usb_deregister_dev(interface, &yurex_class); /* prevent more I/O from starting */ + dev_info(&interface->dev, "Before poison\n"); + usb_poison_urb(dev->urb); + dev_info(&interface->dev, "After poison\n"); mutex_lock(&dev->io_mutex); dev->interface = NULL; mutex_unlock(&dev->io_mutex);
