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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED120C7EE43 for ; Mon, 12 Jun 2023 23:52:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236764AbjFLXw6 (ORCPT ); Mon, 12 Jun 2023 19:52:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231449AbjFLXw5 (ORCPT ); Mon, 12 Jun 2023 19:52:57 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D2E01713 for ; Mon, 12 Jun 2023 16:52:55 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-56cea71b98fso41136527b3.0 for ; Mon, 12 Jun 2023 16:52:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686613974; x=1689205974; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=uEFBZqLeOnIerekrccz1lLmd8Qe7x3UoGwlW9bvhl44=; b=74uw2p5KDfHpf77SJVASj5uH76Ilvhf8JMHoUd9hNY4bzbEdPddbUR68jtbbJnKFsM gDIWe5FzLrY16wmXdA2kSlMQohD4Sf/24Mm1XVRBvr3UyNkrRqEPLVyoGmDhW+Sfp8yp P1wiPuquT7/7+IjfiJx6Wbd0C8KQUHkSsanNbHDpnZbRVc7MDRFv+WB4agCvZ3BNE7bl yLvBH9ckD4qAuruf8TpfR5yFn37hspUeIEFSEB1R1CBbRS2hiwhecagfkEfo/CXv+X+Z vIy69c59exvRUyffGsAhO8qmPISg9DJhH4iBBDAXPvE7ymbg07gwyOIyNByaCTX3Y3Oq t4+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686613974; x=1689205974; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=uEFBZqLeOnIerekrccz1lLmd8Qe7x3UoGwlW9bvhl44=; b=E3q1b5fmNQ+TnuYeV3npWlngXNc4h8omnVDPW37Ako2abYKDWuHtLI99DpDfIbpLML 3ibJ0QYrKZcX5v3eQB8AaSU9ygcJc/qY1yAcbRRTdh3KVB4kkPdhhpktDr3RYrWc5IpH DHgKp/o+tY/fZ+VJcsj3FRp83keVm95h3IqlIEwSYkmDj940AwPOb1nlE8tYXFkfn5OR xLgEHunJDZepnvmoK2bkA3ICA5XztFg17ubL0TBYYiDJah8RQFN1OCktNfNleeA7TlDe U+rb46g+P5YvzOW/zSRndubkRaUA/6zXocV7cpklS3MyUw1ZkH2mwpgJ6Sz6WuoKfNm5 lQzg== X-Gm-Message-State: AC+VfDxbkQFP0+TI2Ki6XToEKqbYMPamczdKeCO2urOy4ytqkn6RXtkK r/lout/7kxRrIWekDXJtRCtERCyvQPI= X-Google-Smtp-Source: ACHHUZ4jeKee0CjUjPElP1qI0aJ+KnIqVQ4G5y9q65QKkFJYHCvJMcSpmAn0PBTGxIHzEQVL0jzKUYM4abA= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a81:e30a:0:b0:56c:f693:9d04 with SMTP id q10-20020a81e30a000000b0056cf6939d04mr84447ywl.10.1686613974687; Mon, 12 Jun 2023 16:52:54 -0700 (PDT) Date: Mon, 12 Jun 2023 16:52:52 -0700 In-Reply-To: <000000000000f316b705fdf6e2b4@google.com> Mime-Version: 1.0 References: <000000000000f316b705fdf6e2b4@google.com> Message-ID: Subject: Re: [syzbot] [kvm?] WARNING in kvm_arch_vcpu_ioctl_run (5) From: Sean Christopherson To: syzbot Cc: bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, jarkko@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org, mingo@redhat.com, pbonzini@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Jun 12, 2023, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 64569520920a Merge tag 'block-6.4-2023-06-09' of git://git.. > git tree: upstream > console+strace: https://syzkaller.appspot.com/x/log.txt?x=12386cd9280000 > kernel config: https://syzkaller.appspot.com/x/.config?x=3c980bfe8b399968 > dashboard link: https://syzkaller.appspot.com/bug?extid=5feef0b9ee9c8e9e5689 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13adcb43280000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13af3853280000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/4421ae3b4ee0/disk-64569520.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/9312cbb35f54/vmlinux-64569520.xz > kernel image: https://storage.googleapis.com/syzbot-assets/3476854febf3/bzImage-64569520.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+5feef0b9ee9c8e9e5689@syzkaller.appspotmail.com > > kvm_intel: L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details. > kvm: vcpu 1: requested 128 ns lapic timer period limited to 200000 ns > kvm: vcpu 1: requested lapic timer restore with starting count register 0x390=1812281087 (231971979136 ns) > initial count (200000 ns). Using initial count to start timer. > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 5004 at arch/x86/kvm/x86.c:11099 kvm_arch_vcpu_ioctl_run+0x2379/0x2820 arch/x86/kvm/x86.c:11099 > Modules linked in: > CPU: 1 PID: 5004 Comm: syz-executor120 Not tainted 6.4.0-rc5-syzkaller-00245-g64569520920a #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 > RIP: 0010:kvm_arch_vcpu_ioctl_run+0x2379/0x2820 arch/x86/kvm/x86.c:11099 KVM doesn't reject KVM_SET_SREGS with a bad CR0, which combined with an L2 that's configured with unrestricted guest *disabled*, coerces KVM into stuffing VM86 state to virtualize Real Mode, and eventually leads to all kinds of weirdness. Will post a patch "shortly" (probably tomorrow at this point).