> 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. > > Thanks, > -- Marco > >> I have been able to reproduce this on a few AMD hosts. >> >>> exact system, I'd ask you to narrow it down by placing 'KCSAN_SANITIZE >>> := n' into suspect subsystems' Makefiles. Once you get it to work with >>> that, we can refine the solution. >>> >>> Thanks, >>> -- Marco
