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=-5.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 6A7F8C47096 for ; Thu, 3 Jun 2021 13:52:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53515613AA for ; Thu, 3 Jun 2021 13:52:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230208AbhFCNyG (ORCPT ); Thu, 3 Jun 2021 09:54:06 -0400 Received: from mga04.intel.com ([192.55.52.120]:51811 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229744AbhFCNyF (ORCPT ); Thu, 3 Jun 2021 09:54:05 -0400 IronPort-SDR: LMDMo8rqObo8LLD3STpRDtoooU/w3CZBAYiAs+4vKUQIg5fYGEJ1zfQxivWtcS+N1uXPfvXMos glFybxiObfSg== X-IronPort-AV: E=McAfee;i="6200,9189,10004"; a="202188128" X-IronPort-AV: E=Sophos;i="5.83,246,1616482800"; d="scan'208";a="202188128" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2021 06:52:21 -0700 IronPort-SDR: fv56pyERrrhKBW/gDO/7lXeQpqsHLUUKL+t9kRcRwUJuqj95ljzowb3MrW9/EFobTBJqLPu0d5 PPU2EdRVXORQ== X-IronPort-AV: E=Sophos;i="5.83,246,1616482800"; d="scan'208";a="550697803" Received: from akleen-mobl1.amr.corp.intel.com (HELO [10.209.7.237]) ([10.209.7.237]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2021 06:52:20 -0700 Subject: Re: [syzbot] KASAN: stack-out-of-bounds Read in profile_pc To: Josh Poimboeuf , Peter Zijlstra Cc: syzbot , bp@alien8.de, hpa@zytor.com, inglorion@google.com, linux-kernel@vger.kernel.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org, Andy Lutomirski , Steven Rostedt References: <00000000000030293b05c39afd6f@google.com> <20210602230054.vyqama2q3koc4bpo@treble> <527ad07e-eec2-a211-03e7-afafe5196100@linux.intel.com> <20210603133914.j2aeadmvhncnlk5q@treble> From: Andi Kleen Message-ID: <0b71d4f9-f707-3d39-c358-7c06c5689a9d@linux.intel.com> Date: Thu, 3 Jun 2021 06:52:19 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <20210603133914.j2aeadmvhncnlk5q@treble> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > True, ftrace does have function profiling (function_profile_enabled). > > Steve, is there a way to enable that on the kernel cmdline? That's not really comparable. function profiling has a lot more overhead. Also there is various code which has ftrace instrumentation disabled. I don't think why you want to kill the old profiler. It's rarely used, but when you need it usually works. It's always good to have simple fall backs. And it's not that it's a lot of difficult code. -Andi