From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id E0CDBDE17F for ; Wed, 20 Aug 2008 07:47:44 +1000 (EST) Subject: Re: ftrace introduces instability into kernel 2.6.27(-rc2,-rc3) From: Benjamin Herrenschmidt To: Mathieu Desnoyers In-Reply-To: <20080819130216.GA18001@Krystal> References: <48591941.4070408@extricom.com> <48A92E15.2080709@extricom.com> <48A9901B.1080900@redhat.com> <48A9BEA3.10906@extricom.com> <20080818184158.GA1798@Krystal> <48AA98E4.6060606@extricom.com> <20080819130216.GA18001@Krystal> Content-Type: text/plain Date: Wed, 20 Aug 2008 07:46:44 +1000 Message-Id: <1219182404.7826.14.camel@pasglop> Mime-Version: 1.0 Cc: Eran Liberty , linux-kernel@vger.kernel.org, rostedt@goodmis.org, linuxppc-dev@ozlabs.org, Steven Rostedt , "Paul E. McKenney" Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > Register GPR30 is always zero... (also true for the other oops) >>From my experiments, -a- non volatile register gets corrupted. Not always the same and not always with the same value. The corruption -seems- to happen due to corruption of the location on the stack where it was saved to / restored from in a previous function call or interrupt. I haven't yet tracked down what actually whacks the stack. Ben.