From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753232AbYHSB5b (ORCPT ); Mon, 18 Aug 2008 21:57:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751832AbYHSB5W (ORCPT ); Mon, 18 Aug 2008 21:57:22 -0400 Received: from gate.crashing.org ([63.228.1.57]:60423 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751546AbYHSB5V (ORCPT ); Mon, 18 Aug 2008 21:57:21 -0400 Subject: Re: ftrace introduces instability into kernel 2.6.27(-rc2,-rc3) From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: Steven Rostedt Cc: Eran Liberty , linuxppc-dev@ozlabs.org, "Paul E. McKenney" , Mathieu Desnoyers , linux-kernel@vger.kernel.org, rostedt@goodmis.org In-Reply-To: <48A9901B.1080900@redhat.com> References: <48591941.4070408@extricom.com> <48A92E15.2080709@extricom.com> <48A9901B.1080900@redhat.com> Content-Type: text/plain Date: Tue, 19 Aug 2008 11:51:32 +1000 Message-Id: <1219110692.8062.0.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2008-08-18 at 11:07 -0400, Steven Rostedt wrote: > Eran Liberty wrote: > > After compiling a kernel with ftrace I started to experience all sorts > > of crashes. > > Just to make sure... > > ftrace enables markers too, and RCU has tracing with the markers. This > may not be the problem, but I just want to eliminate as many variables > as possible. > Could you disable ftrace, but keep the markers on too. Also, could you > enable ftrace again and turn on the FTRACE_STARTUP_TEST. I spent some time last week tracking one of those crashes and it appears that we are getting corruption of some of the non-volatile registers. So far, I found out that it -seems- to be coming from stack frame corruption during a timer interrupt. I haven't had a chance to dig further yet. Cheers, Ben.