> On Apr 9, 2020, at 5:28 PM, Qian Cai <cai@xxxxxx> wrote: > > > >> On Apr 9, 2020, at 12:03 PM, Marco Elver <elver@xxxxxxxxxx> wrote: >> >> On Thu, 9 Apr 2020 at 17:30, Qian Cai <cai@xxxxxx> wrote: >>> >>> >>> >>>> On Apr 9, 2020, at 11:22 AM, Marco Elver <elver@xxxxxxxxxx> wrote: >>>> >>>> On Thu, 9 Apr 2020 at 17:10, Qian Cai <cai@xxxxxx> wrote: >>>>> >>>>> >>>>> >>>>>> On Apr 9, 2020, at 3:03 AM, Marco Elver <elver@xxxxxxxxxx> wrote: >>>>>> >>>>>> On Wed, 8 Apr 2020 at 23:29, Qian Cai <cai@xxxxxx> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> On Apr 8, 2020, at 5:25 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: >>>>>>>> >>>>>>>> On 08/04/20 22:59, Qian Cai wrote: >>>>>>>>> Running a simple thing on this AMD host would trigger a reset right away. >>>>>>>>> Unselect KCSAN kconfig makes everything work fine (the host would also >>>>>>>>> reset If only "echo off > /sys/kernel/debug/kcsan” before running qemu-kvm). >>>>>>>> >>>>>>>> Is this a regression or something you've just started to play with? (If >>>>>>>> anything, the assembly language conversion of the AMD world switch that >>>>>>>> is in linux-next could have reduced the likelihood of such a failure, >>>>>>>> not increased it). >>>>>>> >>>>>>> I don’t remember I had tried this combination before, so don’t know if it is a >>>>>>> regression or not. >>>>>> >>>>>> What happens with KASAN? My guess is that, since it also happens with >>>>>> "off", something that should not be instrumented is being >>>>>> instrumented. >>>>> >>>>> No, KASAN + KVM works fine. >>>>> >>>>>> >>>>>> What happens if you put a 'KCSAN_SANITIZE := n' into >>>>>> arch/x86/kvm/Makefile? Since it's hard for me to reproduce on this >>>>> >>>>> Yes, that works, but this below alone does not work, >>>>> >>>>> KCSAN_SANITIZE_kvm-amd.o := n >>>> >>>> There are some other files as well, that you could try until you hit >>>> the right one. >>>> >>>> But since this is in arch, 'KCSAN_SANITIZE := n' wouldn't be too bad >>>> for now. If you can't narrow it down further, do you want to send a >>>> patch? >>> >>> No, that would be pretty bad because it will disable KCSAN for Intel >>> KVM as well which is working perfectly fine right now. It is only AMD >>> is broken. >> >> Interesting. Unfortunately I don't have access to an AMD machine right now. >> >> Actually I think it should be: >> >> KCSAN_SANITIZE_svm.o := n >> KCSAN_SANITIZE_pmu_amd.o := n >> >> If you want to disable KCSAN for kvm-amd. > > KCSAN_SANITIZE_svm.o := n > > That alone works fine. I am wondering which functions there could trigger > perhaps some kind of recursing with KCSAN? Another data point is set CONFIG_KCSAN_INTERRUPT_WATCHER=n alone also fixed the issue. I saw quite a few interrupt related function in svm.c, so some interrupt-related recursion going on?
