From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757819Ab3KHVHM (ORCPT ); Fri, 8 Nov 2013 16:07:12 -0500 Received: from mail-qe0-f49.google.com ([209.85.128.49]:53293 "EHLO mail-qe0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756963Ab3KHVHH (ORCPT ); Fri, 8 Nov 2013 16:07:07 -0500 Date: Fri, 8 Nov 2013 16:15:21 -0500 (EST) From: Vince Weaver To: Frederic Weisbecker cc: Vince Weaver , Steven Rostedt , LKML , Ingo Molnar , Peter Zijlstra , Dave Jones Subject: Re: perf/tracepoint: another fuzzer generated lockup In-Reply-To: <20131108204839.GD14606@localhost.localdomain> Message-ID: References:

<20131108200244.GB14606@localhost.localdomain> <20131108204839.GD14606@localhost.localdomain> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323329-1390236409-1383945323=:16519" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1390236409-1383945323=:16519 Content-Type: TEXT/PLAIN; charset=US-ASCII On Fri, 8 Nov 2013, Frederic Weisbecker wrote: > On Fri, Nov 08, 2013 at 03:23:07PM -0500, Vince Weaver wrote: > > On Fri, 8 Nov 2013, Frederic Weisbecker wrote: > > > > > > There seem to be a loop that takes too long in intel_pmu_handle_irq(). Your two > > > previous reports seemed to suggest that lbr is involved, but not this one. > > > > I may be wrong but I think everything between and is just > > noise from the NMI perf-event watchdog timer kicking in. > > Ah good point. > > So the pattern seem to be that irq work/perf_event_wakeup is involved, may be > interrupting a tracepoint event or so. I managed to construct a reproducible test case, which is attached. I sometimes have to run it 5-10 times before it triggers. > It would be nice if you enable CONFIG_FRAME_POINTER in your future reports > so that we get more precise traces. Or may be you actually enabled it and it > doesn't work? No, it's not enabled, I can try setting that in the future. 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