From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761320Ab2FEC17 (ORCPT ); Mon, 4 Jun 2012 22:27:59 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:13872 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757680Ab2FEC15 (ORCPT ); Mon, 4 Jun 2012 22:27:57 -0400 X-Authority-Analysis: v=2.0 cv=D8PF24tj c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=jIxPWWKfvXQA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=ayC55rCoAAAA:8 a=VwQbUJbxAAAA:8 a=TVbs_bi3kavZjbBWH68A:9 a=PUjeQqilurYA:10 a=LI9Vle30uBYA:10 a=jeBq3FmKZ4MA:10 a=Ql5RvfvZTJA6iwSd:21 a=2ZDeOC9QpsxXrtaw:21 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1338863274.13348.530.camel@gandalf.stny.rr.com> Subject: [PATCH] powerpc/ftrace: Do not trace restore_interrupts() From: Steven Rostedt To: LKML , linuxppc-dev Cc: Benjamin Herrenschmidt , stable@kernel.org Date: Mon, 04 Jun 2012 22:27:54 -0400 Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As I was adding code that affects all archs, I started testing function tracer against PPC64 and found that it currently locks up with 3.4 kernel. I figured it was due to tracing a function that shouldn't be, so I went through the following process to bisect to find the culprit: cat /debug/tracing/available_filter_functions > t num=`wc -l t` sed -ne "1,${num}p" t > t1 let num=num+1 sed -ne "${num},$p" t > t2 cat t1 > /debug/tracing/set_ftrace_filter echo function /debug/tracing/current_tracer It finally came down to this function: restore_interrupts() I'm not sure why this locks up the system. It just seems to prevent scheduling from occurring. Interrupts seem to still work, as I can ping the box. But all user processes freeze. When restore_interrupts() is not traced, function tracing works fine. Cc: stable@kernel.org Signed-off-by: Steven Rostedt diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 641da9e..64eec59 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -277,7 +277,7 @@ EXPORT_SYMBOL(arch_local_irq_restore); * NOTE: This is called with interrupts hard disabled but not marked * as such in paca->irq_happened, so we need to resync this. */ -void restore_interrupts(void) +void notrace restore_interrupts(void) { if (irqs_disabled()) { local_paca->irq_happened |= PACA_IRQ_HARD_DIS;