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. Thanks, -- Marco
