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 2E5F6C43217 for ; Thu, 1 Dec 2022 12:59:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230266AbiLAM71 (ORCPT ); Thu, 1 Dec 2022 07:59:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230323AbiLAM7P (ORCPT ); Thu, 1 Dec 2022 07:59:15 -0500 Received: from us.icdsoft.com (us.icdsoft.com [192.252.146.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 584E6BB7E5 for ; Thu, 1 Dec 2022 04:59:00 -0800 (PST) Received: (qmail 13748 invoked by uid 1001); 1 Dec 2022 12:58:59 -0000 Received: from unknown (HELO ?94.155.37.249?) (famzah@icdsoft.com@94.155.37.249) by 192.252.159.165 with ESMTPA; 1 Dec 2022 12:58:59 -0000 Message-ID: <212daa8e-8f48-30d9-cfc8-ee5c2025f02c@icdsoft.com> Date: Thu, 1 Dec 2022 14:58:38 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [tip: x86/fpu] x86/fpu/xstate: Define new functions for clearing fpregs and xstates Content-Language: en-US To: Dave Hansen , Thomas Gleixner , "Yu, Yu-cheng" , Andy Lutomirski , LKML Cc: linux-tip-commits@vger.kernel.org, Fenghua Yu , Borislav Petkov , Dave Hansen , Tony Luck , x86 , "Shankar, Ravi V" References: <20200512145444.15483-6-yu-cheng.yu@intel.com> <158964181793.17951.15480349640697746223.tip-bot2@tip-bot2> <10a553a5-699f-6921-705e-9afa1a8e42de@intel.com> <87y2c28zir.ffs@nanos.tec.linutronix.de> <31b30c00-9de9-2881-53c3-b08804571d6c@intel.com> From: Ivan Zahariev In-Reply-To: <31b30c00-9de9-2881-53c3-b08804571d6c@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 29.11.2022 г. 20:16, Dave Hansen wrote: > On 11/29/22 03:19, Ivan Zahariev wrote: >> Can you please take a look into this bug which syzbot tracked to a >> commit of yours (b860eb8dce5906b14e3a7f3c771e0b3d6ef61b94). Even since >> we switched from kernel 4.14 to 5.15 we are experiencing often random >> segmentation faults with the following error in "dmesg": > Which kernel are you running, exactly? There is a fix for the commit > that you identified: > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=484cea4f362e > but it should have been in 5.15. We are running 5.15.75 (LTS) but the problem started when we upgraded from 5.15.31 to 5.15.59 and is present ever since. I erroneously said that it's present into every 5.15. I didn't do my homework well and blamed the commit by Yu-cheng Yu. But this commit never landed into 5.15, nor the fix commit that you referred. There are no functions fpu__clear_all(), copy_init_fpstate_to_fpregs(), copy_user_to_xstate() anywhere in the sources of 5.15.75 or 5.15.31, so the 5.15 kernel is running with a different FPU implementation. Additionally, I tested the reproducer on older 5.15 kernels and on the super-stable 4.14.256. They all emit the same "dmesg" error, so the reproducer is not reliable to detect our problem. I am sorry for wasting your time. > Is there a chance you could test current mainline and see if the issue > is still there? That's our only option, it seems. Thank you. Best regards. --Ivan