On Wed, Oct 10, 2018 at 8:41 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > On Wed, Oct 3, 2018 at 1:21 AM, Shuah Khan <shuah@xxxxxxxxxx> wrote: >> 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? > > By "complete" you mean "from the boot"? If yes, then no, we don't keep > it, full output can be huge and it's not a moving part. > > I've captured boot output from another similar machine, unfortunately > dmesg buffer is not large enough to fit it all, so not sure if you > will find what you are looking for there: > https://gist.githubusercontent.com/dvyukov/11b83aeda0466a0f171451d86ab36e15/raw/57121db6cf1bbb5e57c08746241b03904bde95f6/gistfile1.txt Here is all vhci stuff in /sys if it help. But it's really just a VM with no hardware, so should be reproducible everywhere. root@syzkaller:~# find /sys -name "*vhci*" /sys/class/misc/vhci /sys/devices/platform/vhci_hcd.15 /sys/devices/platform/vhci_hcd.13 /sys/devices/platform/vhci_hcd.8 /sys/devices/platform/vhci_hcd.11 /sys/devices/platform/vhci_hcd.6 /sys/devices/platform/vhci_hcd.4 /sys/devices/platform/vhci_hcd.2 /sys/devices/platform/vhci_hcd.0 /sys/devices/platform/vhci_hcd.14 /sys/devices/platform/vhci_hcd.9 /sys/devices/platform/vhci_hcd.12 /sys/devices/platform/vhci_hcd.7 /sys/devices/platform/vhci_hcd.10 /sys/devices/platform/vhci_hcd.5 /sys/devices/platform/vhci_hcd.3 /sys/devices/platform/vhci_hcd.1 /sys/devices/virtual/misc/vhci /sys/bus/platform/devices/vhci_hcd.15 /sys/bus/platform/devices/vhci_hcd.13 /sys/bus/platform/devices/vhci_hcd.8 /sys/bus/platform/devices/vhci_hcd.11 /sys/bus/platform/devices/vhci_hcd.6 /sys/bus/platform/devices/vhci_hcd.4 /sys/bus/platform/devices/vhci_hcd.2 /sys/bus/platform/devices/vhci_hcd.0 /sys/bus/platform/devices/vhci_hcd.14 /sys/bus/platform/devices/vhci_hcd.9 /sys/bus/platform/devices/vhci_hcd.12 /sys/bus/platform/devices/vhci_hcd.7 /sys/bus/platform/devices/vhci_hcd.10 /sys/bus/platform/devices/vhci_hcd.5 /sys/bus/platform/devices/vhci_hcd.3 /sys/bus/platform/devices/vhci_hcd.1 /sys/bus/platform/drivers/vhci_hcd /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.15 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.13 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.8 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.11 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.6 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.4 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.2 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.0 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.14 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.9 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.12 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.7 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.10 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.5 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.3 /sys/bus/platform/drivers/vhci_hcd/vhci_hcd.1 /sys/module/hci_vhci
