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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 B4073C4360F for ; Wed, 3 Apr 2019 15:13:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8279D2075E for ; Wed, 3 Apr 2019 15:13:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BCy7AnfS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726489AbfDCPNV (ORCPT ); Wed, 3 Apr 2019 11:13:21 -0400 Received: from mail-lj1-f176.google.com ([209.85.208.176]:36969 "EHLO mail-lj1-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725990AbfDCPNV (ORCPT ); Wed, 3 Apr 2019 11:13:21 -0400 Received: by mail-lj1-f176.google.com with SMTP id v13so15235376ljk.4 for ; Wed, 03 Apr 2019 08:13:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=q4+ELUeI9XqzsIFrW1Yov7j70MDy7sYet0rClq9sbIU=; b=BCy7AnfSEpoggVO2Kb9VPO0zsSDtEMfdzt3phhnTSynkec8yszAqxGNS1JdPxZALzb Lnci3wkRhnyUkzGdu+bXygB4/PqRmFhsctSbmqMxXyL5ISLfM1US6IOgWKfSvkkrCqWm 7UFKvxNTU89x3GGaLr1eqt0yyZ0G1hZKqsAYBs+anAAxt1+mZV26Lf9xjosT20jMQpb5 q1euvDSkH92flbqdY6iiazouIesdo69o5CKBGv26nmyA4SuTG9Cg2sidB/p5kNg34ojd TgCoHbvDVhyvey/cPvNknCHhhMOsDLWrBxxvvggTOCKWez9D5s/WPtyM4Q6NMU5zTaiC nKBQ== 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:user-agent; bh=q4+ELUeI9XqzsIFrW1Yov7j70MDy7sYet0rClq9sbIU=; b=MkRsY1uuu61MU8sbQWfSIZNc9LLDlGooLb4BX4CjwfZy5f2U2x/aoYiMmQgPePwVeX 2ChxYm2F2Rp6+JTNqTOEQXxtvA6O48IWZIrX8ePQKJg1n4jhSpOkKAC5egZo/Lu060r+ f/KPBLsONHk/Gs+ltNT7Djgm+1XIbrEpzaSwJvCNOAit8Xk+NyStTnJzWF+W1jDXGr+X /+YkyzgMTibAfyTN6sR/ff2ezlVjUkkedx4GKbfwRhy5KOzZfBS7WJNHy7u0ceUTkO8I Qi7FXcI6HXJ2coy2wjkJBNXatuKHlw3V+9GTttqmKE9KB9TgEX3YohdcmZvWj5gCfdrX GYmQ== X-Gm-Message-State: APjAAAXjktAi3HAi3TqpDxbso+ZEaEi7gp/y5zMatNMFpgT2jVS2TpXd FDJ7gul/YCzHJXCKG90eKb8= X-Google-Smtp-Source: APXvYqzsurfdl5eSpzhnaAMrIUtR5Hu2xi7qBbbI+QuQ/HkQaf6sFuGTVJuCPa3YK6YgsX2BxlPn8g== X-Received: by 2002:a2e:810d:: with SMTP id d13mr160427ljg.93.1554304399374; Wed, 03 Apr 2019 08:13:19 -0700 (PDT) Received: from uranus.localdomain ([5.18.103.226]) by smtp.gmail.com with ESMTPSA id j28sm3260865lfh.81.2019.04.03.08.13.18 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 03 Apr 2019 08:13:18 -0700 (PDT) Received: by uranus.localdomain (Postfix, from userid 1000) id 1178246041B; Wed, 3 Apr 2019 18:13:18 +0300 (MSK) Date: Wed, 3 Apr 2019 18:13:18 +0300 From: Cyrill Gorcunov To: Vince Weaver Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Alexander Shishkin , Ingo Molnar , Borislav Petkov , Namhyung Kim , Thomas Gleixner , Jiri Olsa , Stephane Eranian Subject: Re: perf: perf_fuzzer crashes on Pentium 4 systems Message-ID: <20190403151317.GG1421@uranus.lan> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 03, 2019 at 10:59:32AM -0400, Vince Weaver wrote: > > so moving this to its own thread. > > There was a two-part question asked. > 1. Can the perf-fuzzer crash a Pentium 4 system > 2. Does anyone care anymore? > > The answer to #1 turns out to be "yes" > I'm not sure about #2 (but it's telling my p4 test system hadn't been > turned on in over 3 years). > > In any case the perf_fuzzer can crash my p4 system within an hour or so. > The debugging from this isn't great, I forget what the preferred debug > things to enable in the kernel hacking menu are. > > Here is one crash that just happened: > > The instruction at RIP is unhelpfully > ./arch/x86/include/asm/processor.h:400 > which is > DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __visible; > > Though looking at the assembly it looks like > p4_pmu_enable_event() is called with NULL as the paramater. > Interesting! I'll look more carefully at evening. As far as I remember we rely on active_mask bit set completely, not sure how it could happen that we get nil here. Thanks for pointing!