From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761301AbZDSOWT (ORCPT ); Sun, 19 Apr 2009 10:22:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759691AbZDSOWI (ORCPT ); Sun, 19 Apr 2009 10:22:08 -0400 Received: from mail-fx0-f158.google.com ([209.85.220.158]:33750 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758622AbZDSOWH (ORCPT ); Sun, 19 Apr 2009 10:22:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=a7yj7HfLcNPhZo4igRocl0gE3q1EZj0y+DLrK3a3MBjclI6InUt7Q4HMXIfJzrC/Aa tNuQ5AdJyTA4kTnbEOT2jo89sQiv0LmRdohtKXblUm9tIasVo6SCupTmRMBXso0mWeHC wtbKsLRllQ6pnjsRTAJ9+ktTAR2v9A2ACxTRg= Date: Sun, 19 Apr 2009 16:22:02 +0200 From: Frederic Weisbecker To: Ingo Molnar Cc: Li Zefan , Steven Rostedt , Zhaolei , Tom Zanussi , KOSAKI Motohiro , LKML , Peter Zijlstra Subject: Re: [PATCH] tracing/core: Add current context on tracing recursion warning Message-ID: <20090419142201.GB6262@nowhere> References: <1240117295-6873-1-git-send-email-fweisbec@gmail.com> <49EAC15E.7080702@cn.fujitsu.com> <20090419123430.GA5967@nowhere> <20090419134927.GA6262@nowhere> <20090419140154.GB28919@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090419140154.GB28919@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 19, 2009 at 04:01:54PM +0200, Ingo Molnar wrote: > It would be nice to have this ... but there's no need to do that > atomic thing - just use printk_once() please. (if we race with > another instance and get two messages that's not a problem) > > Ingo Ah, indeed I forgot about printk_once() I've updated the repo with the following v2 on: git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing tracing/recursion --- >>From e894732989e345ea012de146c37d71dd7ed3575d Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 19 Apr 2009 16:18:16 +0200 Subject: [PATCH v2] tracing/core: Add current context on tracing recursion warning In case of tracing recursion detection, we only get the stacktrace. But the current context may be very useful to debug the issue. This patch adds the softirq/hardirq/nmi context with the warning using lockdep context display to have a familiar output. v2: Use printk_once() [ Impact: more information in tracing recursion ] Signed-off-by: Frederic Weisbecker --- kernel/trace/ring_buffer.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index b421b0e..e315178 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1495,6 +1495,16 @@ static int trace_recursive_lock(void) if (unlikely(current->trace_recursion & (1 << level))) { /* Disable all tracing before we do anything else */ tracing_off_permanent(); + + printk_once(KERN_WARNING "Tracing recursion: " + "[HC%u[%lu]:SC%u[%lu]:NMI[%lu]:HE%u:SE%u]\n", + current->hardirq_context, + hardirq_count() >> HARDIRQ_SHIFT, + current->softirq_context, + softirq_count() >> SOFTIRQ_SHIFT, + in_nmi(), current->hardirqs_enabled, + current->softirqs_enabled); + WARN_ON_ONCE(1); return -1; } -- 1.6.1