Date: Fri, 26 Dec 2008 20:58:04 +0530
From: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Yinghai Lu <yinghai@kernel.org>, David Howells <dhowells@redhat.com>,
       mingo@elte.hu, Andrew Morton <akpm@linux-foundation.org>,
       Stephen Rothwell <sfr@canb.auug.org.au>, linux-next@vger.kernel.org,
       LKML <linux-kernel@vger.kernel.org>, mel@csn.ul.ie
Subject: Re: [BUG] next-20081216 - WARNING: at kernel/smp.c:333
	smp_call_function_mask
Message-ID: <20081226152804.GB5100@linux.vnet.ibm.com>
Reply-To: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
References: <86802c440812190351q3118516aif664dd5869c21b2a@mail.gmail.com> <20081219134636.GA11772@linux.vnet.ibm.com> <494C0BF0.3080109@kernel.org> <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>
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* Sam Ravnborg <sam@ravnborg.org> [2008-12-26 11:27:16]:

> On Fri, Dec 26, 2008 at 02:05:47AM -0800, Yinghai Lu wrote:
> > Kamalesh Babulal wrote:
> > > * Yinghai Lu <yinghai@kernel.org> [2008-12-24 12:34:41]:
> > > 
> > >> --
> > > 
> > > After the applying the patch, the kernel panic's with the same backtrace. The
> > > box is running Fedora 5 on it.
> > > 
> > 
> > please try...
> > Ingo, do we need to switch to use #idef and inline function instead?
> 
> I recall David Howells had a similar issue with the bootparamter patch set.
> The workaround he used was to add a barrier(); call in the weak function
> to avoid the inline.
> 
> [full context kept as I added David to to: list].
> 	Sam
> 

Hi Yinghai,

	Thanks, after applying the patch, the kernel boot's up fine.

> > 
> > YH
> > 
> > 
> > [PATCH] sparseirq: add printk to workaround compiler optimizing
> > 
> > Impact: fix panic on null pointer with sparseirq
> > 
> > some compiler seems to inline the weak global function.
> > try to workaround it
> > 
> > also remove duplicated arch_early_irq_init()
> > already have one weak copy in init/main.c
> > 
> > Signed-off-by: Yinghai <yinghai@kernel.org>
> > 
> > ---
> >  init/main.c         |    2 ++
> >  kernel/irq/handle.c |    7 ++-----
> >  2 files changed, 4 insertions(+), 5 deletions(-)
> > 
> > Index: linux-2.6/init/main.c
> > ===================================================================
> > --- linux-2.6.orig/init/main.c
> > +++ linux-2.6/init/main.c
> > @@ -544,10 +544,12 @@ void __init __weak thread_info_cache_ini
> >  
> >  void __init __weak arch_early_irq_init(void)
> >  {
> > +	printk(KERN_DEBUG "calling __weak arch_early_irq_init\n");
> >  }
> >  
> >  void __init __weak early_irq_init(void)
> >  {
> > +	printk(KERN_DEBUG "calling __weak early_irq_init\n");
> >  	arch_early_irq_init();
> >  }
> >  
> > Index: linux-2.6/kernel/irq/handle.c
> > ===================================================================
> > --- linux-2.6.orig/kernel/irq/handle.c
> > +++ linux-2.6/kernel/irq/handle.c
> > @@ -56,10 +56,6 @@ void handle_bad_irq(unsigned int irq, st
> >  int nr_irqs = NR_IRQS;
> >  EXPORT_SYMBOL_GPL(nr_irqs);
> >  
> > -void __init __attribute__((weak)) arch_early_irq_init(void)
> > -{
> > -}
> > -
> >  #ifdef CONFIG_SPARSE_IRQ
> >  static struct irq_desc irq_desc_init = {
> >  	.irq	    = -1,
> > @@ -90,8 +86,9 @@ void init_kstat_irqs(struct irq_desc *de
> >  		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)
> >  {
> > +	printk(KERN_DEBUG "calling __weak arch_init_chip_data\n");
> >  }
> >  
> >  static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
> > --

-- 
Thanks & Regards,
Kamalesh Babulal,
Linux Technology Center,
IBM, ISTL.
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