From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753106AbYIXI7T (ORCPT ); Wed, 24 Sep 2008 04:59:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751510AbYIXI7J (ORCPT ); Wed, 24 Sep 2008 04:59:09 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:38691 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751234AbYIXI7I (ORCPT ); Wed, 24 Sep 2008 04:59:08 -0400 Date: Wed, 24 Sep 2008 10:58:48 +0200 From: Ingo Molnar To: =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker Cc: linux-kernel@vger.kernel.org, Steven Rostedt , Steven Noonan , Arjan van de Ven , Thomas Gleixner , "H. Peter Anvin" , Peter Zijlstra Subject: Re: [Patch -tip 0/4] Creation of the initcall tracer Message-ID: <20080924085848.GA22251@elte.hu> References: <48D8C516.4090706@gmail.com> <20080923100034.GA23118@elte.hu> <20080923193106.GA21422@elte.hu> <48DA0A09.5080709@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <48DA0A09.5080709@gmail.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 * Frédéric Weisbecker wrote: > Ingo Molnar a écrit : > > * Ingo Molnar wrote: > > > >> i've integrated tip/tracing/fastboot into tip/master and have started > >> testing it. It passed the basic tests already so i've just pushed out > >> the new tip/master. Please double-check that i have not messed up the > >> rename or the integration somewhere. > > > > FYI, -tip testing found a boot hang with CONFIG_BOOT_TRACER=y, on a > > 32-bit T60 laptop. I've attached the config that provokes the hang. (you > > need initcall_debug on the boot commandline) > > > > The hang always happens after a specific initcall, shortly after tracing > > is enabled. It just hangs indefinitely there, the last line displayed > > was: > > > > [ 0.004017] initcall ehci_hcd_init+0x0/0x80 returned 0 after 228 msecs > > > > it should have printed this next: > > > > [ 0.808024] calling ohci_hcd_mod_init+0x0/0x80 @ 10 > > > > but that line is never printed. > > > > i've bisected the hang down to this specific commit: > > > > | 35df98dfe2b2503436a8cfda301657810df50a3a is first bad commit > > | commit 35df98dfe2b2503436a8cfda301657810df50a3a > > | Author: Frédéric Weisbecker > > | Date: Tue Sep 23 11:38:18 2008 +0100 > > | > > | tracing/ftrace: launch boot tracing after pre-smp initcalls > > > > An idea: maybe the boot tracer is interacting with the ftrace self-tests > > somehow? CONFIG_FTRACE_SELFTEST=y is enabled. > > > > another thing i noticed is that the sysprof tracer was initialized and > > self-tested shortly before the hang occured. Might be unrelated. > > > > the bisection log is: > > > > # bad: [6522eab5] Merge branch 'x86/uv' > > # good: [699b81f5] Merge branch 'x86/iommu' > > # bad: [8007aae9] timers: fix build error in !oneshot case > > # good: [7f29b23d] Merge branch 'core/rcu' > > # bad: [a54f17e3] manual merge of tracing/fastboot > > # good: [bcbbe946] tracing/ftrace: make tracing suitable to run the b > > # good: [d7095e5a] Merge branch 'fastboot' > > # bad: [35df98df] tracing/ftrace: launch boot tracing after pre-smp > > # good: [42aaa6be] tracing/ftrace: give an entry on the config for bo > > > > Ingo > > > Ingo Molnar a écrit : > > * Ingo Molnar wrote: > > > >> i've integrated tip/tracing/fastboot into tip/master and have started > >> testing it. It passed the basic tests already so i've just pushed out > >> the new tip/master. Please double-check that i have not messed up the > >> rename or the integration somewhere. > > > > FYI, -tip testing found a boot hang with CONFIG_BOOT_TRACER=y, on a > > 32-bit T60 laptop. I've attached the config that provokes the hang. (you > > need initcall_debug on the boot commandline) > > > > The hang always happens after a specific initcall, shortly after tracing > > is enabled. It just hangs indefinitely there, the last line displayed > > was: > > > > [ 0.004017] initcall ehci_hcd_init+0x0/0x80 returned 0 after 228 msecs > > > > it should have printed this next: > > > > [ 0.808024] calling ohci_hcd_mod_init+0x0/0x80 @ 10 > > > > but that line is never printed. > > > > i've bisected the hang down to this specific commit: > > > > | 35df98dfe2b2503436a8cfda301657810df50a3a is first bad commit > > | commit 35df98dfe2b2503436a8cfda301657810df50a3a > > | Author: Frédéric Weisbecker > > | Date: Tue Sep 23 11:38:18 2008 +0100 > > | > > | tracing/ftrace: launch boot tracing after pre-smp initcalls > > > > An idea: maybe the boot tracer is interacting with the ftrace self-tests > > somehow? CONFIG_FTRACE_SELFTEST=y is enabled. > > > > another thing i noticed is that the sysprof tracer was initialized and > > self-tested shortly before the hang occured. Might be unrelated. > > > > the bisection log is: > > > > # bad: [6522eab5] Merge branch 'x86/uv' > > # good: [699b81f5] Merge branch 'x86/iommu' > > # bad: [8007aae9] timers: fix build error in !oneshot case > > # good: [7f29b23d] Merge branch 'core/rcu' > > # bad: [a54f17e3] manual merge of tracing/fastboot > > # good: [bcbbe946] tracing/ftrace: make tracing suitable to run the b > > # good: [d7095e5a] Merge branch 'fastboot' > > # bad: [35df98df] tracing/ftrace: launch boot tracing after pre-smp > > # good: [42aaa6be] tracing/ftrace: give an entry on the config for bo > > > > Ingo > > > > Hehe! I was preparing a patch because I saw last night that the self-tests were reseting and touching the ring-buffer during the initcall tracing. > And now I can see the results of this problem.... > > Following is a patch that should fix it. applied to tip/tracing/fastboot, thanks Frédéric! Ingo