From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755110Ab0JYMdK (ORCPT ); Mon, 25 Oct 2010 08:33:10 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:49128 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751903Ab0JYMdI (ORCPT ); Mon, 25 Oct 2010 08:33:08 -0400 Date: Mon, 25 Oct 2010 14:32:48 +0200 From: Ingo Molnar To: Peter Zijlstra Cc: Steven Rostedt , Jason Baron , LKML , Andrew Morton , Frederic Weisbecker , Thomas Gleixner , "H. Peter Anvin" , Arnaldo Carvalho de Melo , masami.hiramatsu.pt@hitachi.com Subject: Re: [PATCH][GIT PULL] tracing: Fix compile issue for trace_sched_wakeup.c Message-ID: <20101025123248.GA5398@elte.hu> References: <20101022182433.GA24637@elte.hu> <20101022183900.GG6498@redhat.com> <20101023200216.GA19324@elte.hu> <1287881618.16971.657.camel@gandalf.stny.rr.com> <20101024112540.GA21267@elte.hu> <20101025085927.GA11025@elte.hu> <20101025093045.GA21997@elte.hu> <20101025114501.GA2000@elte.hu> <20101025121059.GA3063@elte.hu> <1288009103.15336.58.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1288009103.15336.58.camel@twins> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Peter Zijlstra wrote: > > i.e. the 'fn(timer)' call crashed. > > Right, and its doing an indirect function call from the first stack entry.. which > would seem to suggest someone scribbled our stack.. The ESP value itself seems generally sane: > > [ 11.980010] ESI: f65bdf50 EDI: f6806a00 EBP: f6806a30 ESP: c13dff04 > > [ 11.980010] Process swapper (pid: 0, ti=c13de000 task=c13e2f20 task.ti=c13de000 As task.ti is 8K aligned (as it should be), and ESP is just a tad off the top of the stack (as it should be: a light timer irq interrupted the idle task). The relevant stack section looks like this: [ 11.980010] c103d297 00000000 c10460c1 c13dff4c ca105369 00000002 ffffffff 7fffffff [ 11.980010] c103d52b ca105369 00000002 ca105369 0000002c f6806a00 00000000 f6806a04 [ 11.980010] ca105369 00000002 ca105369 00000002 00000000 f6805dac 00000000 c1420788 and that 00000000 value after c103d297 seems to be the called fn(). The stack content looks sane as well - we have the NULL entry, then various other, good looking entries that dont look corrupted per se. So either there's a 4 byte corruption of the stack, or the place where we took 'fn' from got corrupted: either the timer structure or the hrtimer per-cpu data area. (More exotic crash scenarios as possible as well, if we consider .text corruption.) Thanks, Ingo