From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932805AbcIHMyS (ORCPT ); Thu, 8 Sep 2016 08:54:18 -0400 Received: from mail-it0-f66.google.com ([209.85.214.66]:32988 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752165AbcIHMyQ (ORCPT ); Thu, 8 Sep 2016 08:54:16 -0400 From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Thu, 8 Sep 2016 08:54:13 -0400 (EDT) X-X-Sender: vince@macbook-air To: Alexander Shishkin cc: Vince Weaver , Ingo Molnar , Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, eranian@google.com, Arnaldo Carvalho de Melo Subject: Re: [PATCH v2 0/5] perf, bts: Fallout from the fuzzer for perf/urgent In-Reply-To: <87eg4ukc5f.fsf@ashishki-desk.ger.corp.intel.com> Message-ID: References: <20160906132353.19887-1-alexander.shishkin@linux.intel.com> <20160906171915.GA8963@gmail.com> <87mvjjka7u.fsf@ashishki-desk.ger.corp.intel.com> <87k2enk1al.fsf@ashishki-desk.ger.corp.intel.com> <87eg4ukc5f.fsf@ashishki-desk.ger.corp.intel.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 8 Sep 2016, Alexander Shishkin wrote: > Vince Weaver writes: > > > On the skylake machine with the original 5 patches I got this after > > continuing to fuzz. Sorry about the lack of frame pointer, next x> > compile will have it enabled. > > > > If it matters, prior to this I hit the unrelated > > [25510.278199] WARNING: CPU: 1 PID: 25405 at kernel/events/core.c:3554 perf_event_read+0x18f/0x1a0 > > > > > > [28682.174684] WARNING: CPU: 7 PID: 31992 at kernel/events/core.c:4961 perf_mmap_close+0x2e1/0x2f0 > > It just keeps on giving, doesn't it. I've got the same thing here during > the night, looking at it again. Did you capture the seed by any chance? It was triggered by Seeding random number generator with 1473284719 /proc/sys/kernel/perf_event_max_sample_rate currently: 1000/s /proc/sys/kernel/perf_event_paranoid currently: 0 To reproduce, try: ./perf_fuzzer -s 30000 -r 1473284719 but in my experience these things don't always reproduce deterministically. I can try reproducing it but I can't right now because overnight the machine locked hard (even sysrq isn't helping) with just the unhelpful message of [70953.494637] ------------[ cut here ]------------ not sure if I have the serial console configured wrong or if it just locks up before it can send anything. Anyway I'll head to the lab after my class and reboot things. Vince