Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751144AbVJNDwE (ORCPT ); Thu, 13 Oct 2005 23:52:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751156AbVJNDwE (ORCPT ); Thu, 13 Oct 2005 23:52:04 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:59070 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1751144AbVJNDwD (ORCPT ); Thu, 13 Oct 2005 23:52:03 -0400 Date: Fri, 14 Oct 2005 05:52:30 +0200 From: Ingo Molnar To: Mark Knecht Cc: Steven Rostedt , linux-kernel@vger.kernel.org Subject: Re: 2.6.14-rc4-rt1 - enable IRQ-off tracing causes kernel to fault at boot Message-ID: <20051014035230.GB6513@elte.hu> References: <5bdc1c8b0510121000i5db112f2p642f66686fb46c57@mail.gmail.com> <20051013073029.GA12801@elte.hu> <5bdc1c8b0510130526k6064c640pecded9ccb0ef7dde@mail.gmail.com> <5bdc1c8b0510131210i64f7f289q557368b056e59e18@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5bdc1c8b0510131210i64f7f289q557368b056e59e18@mail.gmail.com> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=AWL autolearn=disabled SpamAssassin version=3.0.4 0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1554 Lines: 36 * Mark Knecht wrote: > Ingo & Steve, > Thank you for your great instructions that even a guitar player > could basically follow. After about an hour of messing around I did > manage to capture the crash. The console file is attached. > > NOTE: The first time I booted the kernel it got to the crash point and > the machine rebooted. The second time it booted I got the trace. Both > boots are in the capture file. thanks, this log is much more informative. No smoking gun though, but it seems something fundamental (probably lowlevel x64 code) has been broken by -rt1. Do the crashes go away if you take the -rc3-rt13 version of arch/x86_64/kernel/entry.S and copy it over into the -rc4-rt1 tree? [this undoes a particular set of CONFIG_CRITICAL_IRQSOFF_TIMING fixes from the x64 code, which i did during -rc3-rt13 => -rc4-rt1] (Note that doing this will re-introduce tracing bugs, which can result in false-positive latency readings - but it should fix any related lowlevel bug in the assembly code.) if this indeed solves the crash then i'd suggest to restore the -rt1 version of entry.S, and i'd suggest to disable CRITICAL_IRQSOFF_TIMING until i fix it. You should be able to get pretty good latency tracing info even without CRITICAL_IRQSOFF_TIMING. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/