On 10/02/2018 10:42 AM, Dmitry Vyukov wrote: > On Tue, Oct 2, 2018 at 6:04 PM, Shuah Khan <shuah@xxxxxxxxxx> wrote: >> On 09/04/2018 12:52 PM, syzbot wrote: >>> Hello, >>> >>> syzbot found the following crash on: >>> >>> HEAD commit: 420f51f4ab6b Merge tag 'arm64-fixes' of git://git.kernel.o.. >>> git tree: upstream >>> console output: https://syzkaller.appspot.com/x/log.txt?x=126a6f0e400000 >>> kernel config: https://syzkaller.appspot.com/x/.config?x=531a917630d2a492 >>> dashboard link: https://syzkaller.appspot.com/bug?extid=bccc1fe10b70fadc78d0 >>> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=121caa46400000 >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14ed8ab6400000 >> >> C producer doesn't reproduce the problem on 4.19-rc5. Does this C producer >> depend on state of the machine? i.e what is the status of vhci_hcd - are >> there any devices attached? > > Hi Shuah, > > syzbot always runs tests reproducers on a clean machine. There is some > state are running a Debian wheezy init, but no test/fuzz/stress > workload is run before the reproducer. > syzbot also uses VMs, so there are no real devices attached. And it's > GCE VMs (not qemu), and I think GCE does not even emulate any USB > devices. > > An obvious thing to try would be to use the exact commit and config > syzbot gave (rather than 4.19-rc5). > You can also take the image syzbot uses here: > https://github.com/google/syzkaller/blob/master/docs/syzbot.md#crash-does-not-reproduce > > >> I can see the problem looking at the code and fix is easy. However, I would >> like be able to reproduce it and verify the fix works. Also this would be a >> good regression for the driver I could consider adding to selftests. > > syzbot can test fixes for bugs with reproducers: > https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches > So it can test your fix. But this obviously won't help with a test. > Tried the same config and no luck. Any chance you have the complete dmesg? thanks, -- Shuah
