From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 957DAC2BB55 for ; Thu, 9 Apr 2020 16:03:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D1DA20768 for ; Thu, 9 Apr 2020 16:03:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hTXModHk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728390AbgDIQDZ (ORCPT ); Thu, 9 Apr 2020 12:03:25 -0400 Received: from mail-oi1-f196.google.com ([209.85.167.196]:37444 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728247AbgDIQDY (ORCPT ); Thu, 9 Apr 2020 12:03:24 -0400 Received: by mail-oi1-f196.google.com with SMTP id u20so311002oic.4 for ; Thu, 09 Apr 2020 09:03:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=tjHIQBCBSrHwNHPc99hMBF0pIDG2KesjmgOXuqoKDMM=; b=hTXModHkfdlX4RpWCP0A8PlGie48zk3lgc/GhvV68BZ/2aFTULVRTRqzfiLrEzbp0c ZKAIlsAUDMHBfH+Tm+tEkVwivavdnnnUlzWGkKC0h8JWKx2uSLpFCRwppcZoCtGZa/HD u2R43yOje8QjZT6SEJmT7a2S8n+s65ArUAGaee5e4pAjrqJwPswZWhJPtmiOYFl8b/TM /rzlesPZIDJRpWedg4VX6ouyELcid/NqcHPreWZWu6uj6TAg5nCUYfwqVRXU+zx+sIq2 gT8LaiWk7S2hJJD3820Bmji/zmlOnTznAOc14FpxaXSXfraYIEA9ZrEmwkkYmGLA9R2c u1RA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=tjHIQBCBSrHwNHPc99hMBF0pIDG2KesjmgOXuqoKDMM=; b=c6EgQsAN/GqovCxOnZeg+dClz9ODJhN60BYyhgnTKJXI0QTtH5abZMAbg/L+MGafRW zGnP7mHK8VaIVV2l/L1ktzIzsymULizITMWp3hd9J+Zf7vhuO0OAsfUnY93S+uOnI+VH MwhwilHla4jLovx7Q9my5Vqyq+Bw5HR5ZsKlKu3cRgvCMqeOdkFtrmH1PY9JuRAuF4mk EZef+D7iti5SC8MjPvmpGlKSZ8kLGLZ+CpZxxi2q8vjH689EaQ+sJnC53I30xBwsFVDK Os3SEV8MAqyIDF3VG7oT/CbVWKsTnNkZ7SuSHnQKyxl1hlxecwye0nH2NYmCEzFllqR1 tn3w== X-Gm-Message-State: AGi0PubKF8fDOYgLOTPl1XFVgJswEYcaxfNhGfjTfV8MatNST7R0SQ+4 NOs+dYLlbScFtjejxDYZwz6Ep0m+IoBlTT808F/dmQ== X-Google-Smtp-Source: APiQypKFcY0QZIxSnMvqOumGL+bCUZQWyP22MGaxw3k465l/nIpOkbNXdj9LwkwU0lNfgWhrUjuExNoRAwBspu6AUvw= X-Received: by 2002:aca:620a:: with SMTP id w10mr1792454oib.121.1586448202131; Thu, 09 Apr 2020 09:03:22 -0700 (PDT) MIME-Version: 1.0 References: <017E692B-4791-46AD-B9ED-25B887ECB56B@lca.pw> <2730C0CC-B8B5-4A65-A4ED-9DFAAE158AA6@lca.pw> In-Reply-To: <2730C0CC-B8B5-4A65-A4ED-9DFAAE158AA6@lca.pw> From: Marco Elver Date: Thu, 9 Apr 2020 18:03:10 +0200 Message-ID: Subject: Re: KCSAN + KVM = host reset To: Qian Cai Cc: Paolo Bonzini , "paul E. McKenney" , kasan-dev , LKML , kvm@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Apr 2020 at 17:30, Qian Cai wrote: > > > > > On Apr 9, 2020, at 11:22 AM, Marco Elver wrote: > > > > On Thu, 9 Apr 2020 at 17:10, Qian Cai wrote: > >> > >> > >> > >>> On Apr 9, 2020, at 3:03 AM, Marco Elver wrote: > >>> > >>> On Wed, 8 Apr 2020 at 23:29, Qian Cai wrote: > >>>> > >>>> > >>>> > >>>>> On Apr 8, 2020, at 5:25 PM, Paolo Bonzini wro= te: > >>>>> > >>>>> On 08/04/20 22:59, Qian Cai wrote: > >>>>>> Running a simple thing on this AMD host would trigger a reset righ= t away. > >>>>>> Unselect KCSAN kconfig makes everything work fine (the host would = also > >>>>>> reset If only "echo off > /sys/kernel/debug/kcsan=E2=80=9D 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 failur= e, > >>>>> not increased it). > >>>> > >>>> I don=E2=80=99t remember I had tried this combination before, so don= =E2=80=99t 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 :=3D 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 :=3D 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 :=3D 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 :=3D n KCSAN_SANITIZE_pmu_amd.o :=3D n If you want to disable KCSAN for kvm-amd. Thanks, -- Marco