From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [BUG] next-20081216 - WARNING: at kernel/smp.c:333 smp_call_function_mask Date: Fri, 26 Dec 2008 19:17:34 +0100 Message-ID: <20081226181733.GA24439@elte.hu> References: <20081223132127.GA5450@linux.vnet.ibm.com> <495153A4.5060201@kernel.org> <20081224163400.GA11562@linux.vnet.ibm.com> <49529CE1.4040005@kernel.org> <20081226091217.GA5100@linux.vnet.ibm.com> <4954AC7B.3020603@kernel.org> <20081226102716.GA31450@uranus.ravnborg.org> <20081226152804.GB5100@linux.vnet.ibm.com> <20081226153318.GA4514@elte.hu> <20081226170452.GC5100@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx3.mail.elte.hu ([157.181.1.138]:57947 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750953AbYLZSSx (ORCPT ); Fri, 26 Dec 2008 13:18:53 -0500 Content-Disposition: inline In-Reply-To: <20081226170452.GC5100@linux.vnet.ibm.com> Sender: linux-next-owner@vger.kernel.org List-ID: To: Kamalesh Babulal Cc: Sam Ravnborg , Yinghai Lu , David Howells , Andrew Morton , Stephen Rothwell , linux-next@vger.kernel.org, LKML , mel@csn.ul.ie * Kamalesh Babulal wrote: > > how about the patch below, does that work too? (after removing > > Yinghai's patch) > > Hi Ingo, > > Kernel crashes with the same trace, after the applying the patch. okay, thanks - does the below cleaner variant of Yinghai's patch solve the problem too? Ingo --------------------> >>From 9c93fc72ec95dc97d65b840978f9d605f4e5823a Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Fri, 26 Dec 2008 02:05:47 -0800 Subject: [PATCH] sparseirq: work around compiler optimizing away __weak functions Impact: fix panic on null pointer with sparseirq Some GCC versions seem to inline the weak global function, when that function is empty. Work it around, by putting a barrier into the function. Signed-off-by: Yinghai Signed-off-by: Ingo Molnar --- init/main.c | 9 +++++++++ kernel/irq/handle.c | 3 ++- 2 files changed, 11 insertions(+), 1 deletions(-) diff --git a/init/main.c b/init/main.c index c1f999a..841d2b2 100644 --- a/init/main.c +++ b/init/main.c @@ -531,20 +531,29 @@ static void __init boot_cpu_init(void) cpu_set(cpu, cpu_possible_map); } +/* + * The barriers are needed to keep a GCC bug from optimizing + * away these weak functions: + */ + void __init __weak smp_setup_processor_id(void) { + barrier(); } void __init __weak thread_info_cache_init(void) { + barrier(); } void __init __weak arch_early_irq_init(void) { + barrier(); } void __init __weak early_irq_init(void) { + barrier(); arch_early_irq_init(); } diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index 06b05a4..a6d16a4 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -86,8 +86,9 @@ void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr) desc->kstat_irqs = (unsigned int *)ptr; } -void __attribute__((weak)) arch_init_chip_data(struct irq_desc *desc, int cpu) +void __weak arch_init_chip_data(struct irq_desc *desc, int cpu) { + barrier(); } static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)