On Thu, 18 Apr 2019, syzbot wrote: > syzbot has found a reproducer for the following crash on: > > HEAD commit: d34f9519 usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan/tree/usb-fuzzer > console output: https://syzkaller.appspot.com/x/log.txt?x=10adfe6b200000 > kernel config: https://syzkaller.appspot.com/x/.config?x=c73d1bb5aeaeae20 > dashboard link: https://syzkaller.appspot.com/bug?extid=2eb9121678bdb36e6d57 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=145cb7e3200000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17f8bd2d200000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+2eb9121678bdb36e6d57@xxxxxxxxxxxxxxxxxxxxxxxxx > > yurex 1-1:0.150: yurex_interrupt - unknown status received: -71 > usb 1-1: USB disconnect, device number 112 > yurex 1-1:0.150: yurex_interrupt - unknown status received: -71 > kasan: CONFIG_KASAN_INLINE enabled > kasan: GPF could be caused by NULL-ptr deref or user memory access > general protection fault: 0000 [#1] SMP KASAN PTI Andrey: 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? And perhaps to run the test with just a single dummy-hcd bus instead of 6? At this point, I suspect the original general protection fault in the yurex driver has been fixed, but something else in dummy-hcd may be causing the rcu-detected stalls. Alan Stern
