Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756437AbYHTMnU (ORCPT ); Wed, 20 Aug 2008 08:43:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753914AbYHTMnH (ORCPT ); Wed, 20 Aug 2008 08:43:07 -0400 Received: from viefep31-int.chello.at ([62.179.121.49]:58674 "EHLO viefep31-int.chello.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753468AbYHTMnG (ORCPT ); Wed, 20 Aug 2008 08:43:06 -0400 Subject: Re: [PATCH] printk: robustify printk From: Peter Zijlstra To: Jiri Kosina Cc: Ingo Molnar , 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 In-Reply-To: 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> Content-Type: text/plain Date: Wed, 20 Aug 2008 14:43:01 +0200 Message-Id: <1219236181.8651.46.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1939 Lines: 53 On Wed, 2008-08-20 at 14:40 +0200, Jiri Kosina wrote: > 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? Indeed, Thanks! > > 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 Acked-by: Peter Zijlstra > --- > > 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/