From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH] softirq: Fix warnings triggered by netconsole Date: Wed, 19 Nov 2008 10:32:24 +0100 Message-ID: <20081119093224.GE22309@elte.hu> References: <87y6zwwy5c.fsf@tac.ki.iif.hu> <20081119084125.GB6699@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Johannes Berg , David Miller , Ferenc Wagner , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Jarek Poplawski Return-path: Received: from mx2.mail.elte.hu ([157.181.151.9]:48387 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524AbYKSJci (ORCPT ); Wed, 19 Nov 2008 04:32:38 -0500 Content-Disposition: inline In-Reply-To: <20081119084125.GB6699@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: * Jarek Poplawski wrote: > Consider netconsole case as special in local_bh_enable()/_disable(). > This patch skips in_irq() and irqs_disabled() warnings for NETPOLL > configs when it's safe wrt. do_softirq(). > > Reported-by: Ferenc Wagner > Signed-off-by: Jarek Poplawski > --- > [apply on top of my first softirq patch in this thread] > > diff -Nurp a/kernel/softirq.c b/kernel/softirq.c > --- a/kernel/softirq.c 2008-11-19 07:33:23.000000000 +0000 > +++ b/kernel/softirq.c 2008-11-19 07:26:28.000000000 +0000 > @@ -76,7 +76,12 @@ static void __local_bh_disable(unsigned > { > unsigned long flags; > > +#ifdef CONFIG_NETPOLL > + if (!softirq_count()) > + WARN_ON_ONCE(in_irq()); > +#else > WARN_ON_ONCE(in_irq()); > +#endif > > raw_local_irq_save(flags); > add_preempt_count(SOFTIRQ_OFFSET); > @@ -138,7 +143,16 @@ static inline void _local_bh_enable_ip(u > #ifdef CONFIG_TRACE_IRQFLAGS > unsigned long flags; > #endif > +#ifdef CONFIG_NETPOLL > + /* > + * Special-case - netconsole runs network code with all interrupts > + * disabled. Warn only if it can be really dangerous: > + */ > + if (softirq_count() == SOFTIRQ_OFFSET) > + WARN_ON_ONCE(in_irq() || irqs_disabled()); > +#else > WARN_ON_ONCE(in_irq() || irqs_disabled()); > +#endif > #ifdef CONFIG_TRACE_IRQFLAGS > local_irq_save(flags); > #endif this is a very ugly patch, not really acceptable. printk methods should not be doing softirq processing - period. Ingo