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 68E79C433EF for ; Wed, 16 Mar 2022 15:34:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344197AbiCPPfa (ORCPT ); Wed, 16 Mar 2022 11:35:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240167AbiCPPf1 (ORCPT ); Wed, 16 Mar 2022 11:35:27 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCAA028E3C for ; Wed, 16 Mar 2022 08:34:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1647444853; x=1678980853; h=message-id:date:mime-version:to:references:from:subject: in-reply-to:content-transfer-encoding; bh=boYCnh6qWuwCAj1Sjfgi0rW0Z9re8P6EPX8iN50WXOw=; b=ihESAcpMJIFO5STBtHDfzvXBuOo1mwgMSmJv6/BbUJzTpVi7YsRR5duV HpAuACApYDYRc31sLYDRP9fgGUrh4XUwcAM7b/n7a+ie8Kg/OY/bDibFa q/H7wo0/a0mfidXqGLUyMI7ss9kQyw3BjwRx5PYCKP/zybv5wdLkHnqXs pbv4Y9rXOvNUmDHtBGzdv448PfsOTNF9RebtivVXEZF6CDycmoZnhFwrV OIILpSczrAJzvPiUYCKlC8mGRyUeZlZbR5BHjFpBzqZocWA9TlvyCaAmF KTKy+6heFcvnWfDi2KZI96sCWJdFcVYj0lttA0ziRk4wNBznwpTrAU4wE Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10286"; a="256822706" X-IronPort-AV: E=Sophos;i="5.90,186,1643702400"; d="scan'208";a="256822706" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2022 08:34:13 -0700 X-IronPort-AV: E=Sophos;i="5.90,186,1643702400"; d="scan'208";a="557502057" Received: from jdwaldem-mobl.amr.corp.intel.com (HELO [10.255.228.230]) ([10.255.228.230]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2022 08:34:12 -0700 Message-ID: Date: Wed, 16 Mar 2022 08:34:04 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Content-Language: en-US To: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Peter Zijlstra References: From: Dave Hansen Subject: Re: system locks up with CONFIG_SLS=Y; 5.17.0-rc In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/16/22 02:51, Jamie Heilman wrote: > I've been (somewhat unsuccessfully) trying to bisect a hard lock-up > of my workstation that occurs when I'm running 5.17 rc kernels a few > seconds after I start a kvm guest instance. There is no output to > any log, everything locks up completely, sysrq doesn't even work > anymore. As bisection progressed closer and closer to the branch > where straight-line-speculation mitigation was enabled, and as bisect > landing me between 9cdbeec40968 ("x86/entry_32: Fix segment exceptions") > and 3411506550b1 ("x86/csum: Rewrite/optimize csum_partial()") wasn't > resulting in clear results (my system definately starts Oopsing and > gets so hosed up that I'm forced to reboot, but it isn't quite as dire > as sysrq continues to function) I decided to just try a build with > CONFIG_SLS disabled, and it turns out that works just fine. Sooo... > > This system uses a Intel Core2 Duo E8400 processor. > working config (CONFIG_SLS=N) and dmesg at: > http://audible.transient.net/~jamie/k/sls.config-5.17.0-rc8 > http://audible.transient.net/~jamie/k/sls.dmesg > > (I don't think the dmesg of CONFIG_SLS=Y is really any different.) If you get really ambitious, you could try to see if any of the individual things that change based on the CONFIG_SLS #ifdef trigger this. Basically, turn off the config option and then go manually enabling each of the sites. The odd thing is that it isn't touching anything really KVM-specific. It probably influences some KVM-specific assembly, but it's hard to see how that might break anything. The worrying part is: ifdef CONFIG_SLS KBUILD_CFLAGS += -mharden-sls=all endif That's presumably a shiny, new compiler option, also known as a relatively lightly tested compiler option.