> 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?
