Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754543AbYHMPSt (ORCPT ); Wed, 13 Aug 2008 11:18:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752202AbYHMPSl (ORCPT ); Wed, 13 Aug 2008 11:18:41 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:42299 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750973AbYHMPSl (ORCPT ); Wed, 13 Aug 2008 11:18:41 -0400 Date: Wed, 13 Aug 2008 17:18:27 +0200 From: Ingo Molnar To: Steven Rostedt Cc: Bruce Duncan , linux-kernel@vger.kernel.org Subject: Re: [git pull] ftrace for v2.6.27 Message-ID: <20080813151827.GA10819@elte.hu> References: <20080714142226.GA11412@elte.hu> <200808130248.58216.bwduncan@gmail.com> <48A2F9AB.8000608@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48A2F9AB.8000608@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 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 Content-Length: 1695 Lines: 45 * Steven Rostedt wrote: > Bruce Duncan wrote: >> Hi Ingo, Steven, everyone, >> >> [ Please CC me in replies ] >> >> I have just tracked down a regression in 2.6.27-rc2 wrt 2.6.26. Commit >> 77a2b37d227483fe52aead242652aee406c25bf0 (ftrace: startup tester on >> dynamic tracing.) causes my laptop to fail to resume from S3 (it simply >> reboots about a second after the resume starts and the display never >> shows anything). >> >> The patch doesn't revert with patch -R (I don't know if there's a >> cleverer way to ask git to revert it), but the problem goes away if I >> turn off CONFIG_DYNAMIC_FTRACE. >> >> The commit and bisect log are attached. Please can you help me to debug this? >> >> >> > > I found that I have a box that displays this bug. Without FTRACE it > suspends and resumes fine. With FTRACE enabled, it does not. > > I'll be actively debugging it now. (unfortunately, as with all new > laptops, I don't have a serial for it). try latest tip/master plus an USB debug key, then enable CONFIG_EARLY_PRINTK_DBGP=y in your .config on the host, add the earlyprintk=dbgp,keep boot parameter and reboot [and disable USB for good measure]. On the other host you connect to via an USB cable, enable USB_SERIAL_DEBUG=y and use /dev/ttyUSB0 with the serial terminal app of your choice. that, as long as the USB ports are operational, gives a working serial console on just about any laptop. 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/