Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756003AbYHTMmm (ORCPT ); Wed, 20 Aug 2008 08:42:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754018AbYHTMmd (ORCPT ); Wed, 20 Aug 2008 08:42:33 -0400 Received: from twin.jikos.cz ([213.151.79.26]:57198 "EHLO twin.jikos.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753901AbYHTMmc (ORCPT ); Wed, 20 Aug 2008 08:42:32 -0400 Date: Wed, 20 Aug 2008 14:40:55 +0200 (CEST) From: Jiri Kosina X-X-Sender: jikos@twin.jikos.cz To: Ingo Molnar cc: Peter Zijlstra , Linus Torvalds , Andrew Morton , tglx@linutronix.de, marcin.slusarz@gmail.com, linux-kernel@vger.kernel.org, davem@davemloft.net, rostedt@goodmis.org, paulmck@linux.vnet.ibm.com Subject: Re: [PATCH] printk: robustify printk In-Reply-To: <20080811115109.GB23529@elte.hu> Message-ID: References: <1218215454.8625.133.camel@twins> <1218217257.29098.2.camel@lappy.programming.kicks-ass.net> <1218219269.29098.5.camel@lappy.programming.kicks-ass.net> <20080808121428.646a8b3c.akpm@linux-foundation.org> <1218223269.29098.12.camel@lappy.programming.kicks-ass.net> <1218224829.29098.19.camel@lappy.programming.kicks-ass.net> <20080811104526.GA15186@elte.hu> <1218452640.10800.58.camel@twins> <20080811115109.GB23529@elte.hu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1734 Lines: 49 On Mon, 11 Aug 2008, Ingo Molnar wrote: > -----------------> > >From b845b517b5e3706a3729f6ea83b88ab85f0725b0 Mon Sep 17 00:00:00 2001 > From: Peter Zijlstra > Date: Fri, 8 Aug 2008 21:47:09 +0200 > Subject: [PATCH] printk: robustify printk > > Avoid deadlocks against rq->lock and xtime_lock by deferring the klogd > wakeup by polling from the timer tick. > > Signed-off-by: Peter Zijlstra > Signed-off-by: Ingo Molnar Then I think we also want the patch below on top of that, right? From: Jiri Kosina printk: robustify printk, fix #3 Remove the comment describing the possibility of printk() deadlocking on runqueue lock. Signed-off-by: Jiri Kosina --- kernel/printk.c | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-) diff --git a/kernel/printk.c b/kernel/printk.c index b51b156..9fbf391 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -577,9 +577,6 @@ static int have_callable_console(void) * @fmt: format string * * This is printk(). It can be called from any context. We want it to work. - * Be aware of the fact that if oops_in_progress is not set, we might try to - * wake klogd up which could deadlock on runqueue lock if printk() is called - * from scheduler code. * * We try to grab the console_sem. If we succeed, it's easy - we log the output and * call the console drivers. If we fail to get the semaphore we place the output -- 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/