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=-13.3 required=3.0 tests=BAYES_00,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 4321DC433E0 for ; Thu, 25 Feb 2021 20:31:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17F9664F70 for ; Thu, 25 Feb 2021 20:31:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234123AbhBYUbT (ORCPT ); Thu, 25 Feb 2021 15:31:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232923AbhBYU0I (ORCPT ); Thu, 25 Feb 2021 15:26:08 -0500 Received: from mail-pf1-x433.google.com (mail-pf1-x433.google.com [IPv6:2607:f8b0:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B68CC0617AA for ; Thu, 25 Feb 2021 12:25:19 -0800 (PST) Received: by mail-pf1-x433.google.com with SMTP id t29so4370514pfg.11 for ; Thu, 25 Feb 2021 12:25:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=JOqIuOkYNfNei5S5ihkPvqbXAibk+FpZz0aihINz3pA=; b=Pv5QWFcnDMm6MJn96nAMy7sFslYSo2nDr7i/1/MdPjuHpBXAqOkl0BNvKi0vaEX3R+ gjsmeuwFfEdF9VzDgG0anLrMVRCTAuWdX1q5gMt9kpRa7sR2PXDxxWCuTilew+CUEqg7 VLechlXjwuNe04aXiUbr4WCoW0ZGtFJgv/7gF9vwUDEd/MzbOclVdcCI/Ej7dz2T/C4T CkiU1V1awnNDPewhPLgRkRgrRvImVbHtBY9WXUP1w3CJafgkfLXdaJxpyzyV311ZmEp9 EZSbtEjV/iBpA+H4LMkrRB9c1DdWw/wghBswPcAfE/UaRNghQrgpZpALBCvqTm3+ZOg/ MqEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=JOqIuOkYNfNei5S5ihkPvqbXAibk+FpZz0aihINz3pA=; b=FPoIlFmf05h7qzolOw1iziAZT3SjleEcAdWVEHeXzCJjL2qn9Fy5Sp6NmVcBezQFlX qbYgWtN1YEJWJ82W0RdsmAeflIeTTn6L4LwpkF/NjmsxKIq1pVl83RtCfWjcFVxzd5d6 w6AY9LW8Y4csDcS8hTUA4L2Lkkdm7IcA1809+p/zyMXYXIJinShb6QUQnAXL29Fkyrt4 v2vLK7j81Dq2WK2Le/lBYtjNHDMHocnU+WP50x2A0Isk7+xJx3W99lPf1Z3DKOD1xYuA VDpn9ljFwLoow6ESNGlhpwrXmM5UsE31kYlfs540rPozMdldYKiGajZCAqwxYH378XyI BAow== X-Gm-Message-State: AOAM531z7bpLnWkcUJAiZy9nes2fEpx6PNf10bCs/hBf/bXief+XnzKY 6NCLz13xo1bX0Voj3LSjBzhThQ== X-Google-Smtp-Source: ABdhPJy+cnuWew3jHbZvwLPnxU5cM+OFZqtAAV1VFVzsI3ExMI5mkd/Cf4oGUQ9jez7G4itguiu9Dw== X-Received: by 2002:a62:ed01:0:b029:1c8:c6c:16f0 with SMTP id u1-20020a62ed010000b02901c80c6c16f0mr4866061pfh.80.1614284718762; Thu, 25 Feb 2021 12:25:18 -0800 (PST) Received: from google.com ([2620:15c:f:10:34c4:7c1d:f9ba:4576]) by smtp.gmail.com with ESMTPSA id h5sm6660099pgv.87.2021.02.25.12.25.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Feb 2021 12:25:18 -0800 (PST) Date: Thu, 25 Feb 2021 12:25:11 -0800 From: Sean Christopherson To: Dmitry Vyukov Cc: Borislav Petkov , syzbot , Dave Hansen , "H. Peter Anvin" , Jim Mattson , Joerg Roedel , "Kirill A. Shutemov" , KVM list , LKML , Lorenzo Stoakes , Ingo Molnar , Paolo Bonzini , syzkaller-bugs , Thomas Gleixner , Vitaly Kuznetsov , wanpengli@tencent.com, the arch/x86 maintainers , syzkaller Subject: Re: general protection fault in vmx_vcpu_run (2) Message-ID: References: <0000000000007ff56205ba985b60@google.com> <00000000000004e7d105bc091e06@google.com> <20210224122710.GB20344@zn.tnic> <20210224174936.GG20344@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 25, 2021, Dmitry Vyukov wrote: > On Wed, Feb 24, 2021 at 7:08 PM 'Sean Christopherson' via > syzkaller-bugs wrote: > > > > On Wed, Feb 24, 2021, Borislav Petkov wrote: > > > Hi Dmitry, > > > > > > On Wed, Feb 24, 2021 at 06:12:57PM +0100, Dmitry Vyukov wrote: > > > > Looking at the bisection log, the bisection was distracted by something else. > > > > > > Meaning the bisection result: > > > > > > 167dcfc08b0b ("x86/mm: Increase pgt_buf size for 5-level page tables") > > > > > > is bogus? > > > > Ya, looks 100% bogus. > > > > > > You can always find the original reported issue over the dashboard link: > > > > https://syzkaller.appspot.com/bug?extid=42a71c84ef04577f1aef > > > > or on lore: > > > > https://lore.kernel.org/lkml/0000000000007ff56205ba985b60@google.com/ > > > > > > Ok, so this looks like this is trying to run kvm ioctls *in* a guest, > > > i.e., nested. Right? > > > > Yep. I tried to run the reproducer yesterday, but the kernel config wouldn't > > boot my VM. I haven't had time to dig in. Anyways, I think you can safely > > assume this is a KVM issue unless more data comes along that says otherwise. > > Interesting. What happens? Does the kernel crash? Userspace crash? > Rootfs is not mounted? Or something else? Not sure, it ended up in the EFI shell instead of the kernel (running with QEMU's -kernel). My QEMU+KVM setup does a variety of shenanigans, I'm guessing it's an incompatibility in my setup.