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Message-ID: <20120521210901.GA25326@sgi.com>
Date: Mon, 21 May 2012 16:09:01 -0500
From: Dimitri Sivanich <sivanich@....com>
To: Suresh Siddha <suresh.b.siddha@...el.com>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
Yinghai Lu <yinghai@...nel.org>,
Naga Chumbalkar <nagananda.chumbalkar@...com>,
Jacob Pan <jacob.jun.pan@...ux.intel.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: check for valid irq_cfg pointer in
smp_irq_move_cleanup_interrupt
On Mon, May 21, 2012 at 02:05:53PM -0700, Suresh Siddha wrote:
> On Mon, 2012-05-21 at 11:49 -0500, Dimitri Sivanich wrote:
> > The smp_irq_move_cleanup_interrupt routine should be checking for a valid
> > irq_cfg pointer prior to accessing it. It also seems that this should be
> > done after taking the desc lock.
>
> I think these changes are correct. Did you see any crashes during module
> unload etc?
Yes, we have seen these on occasion during boot.
>
> Reviewed-by: Suresh Siddha <suresh.b.siddha@...el.com>
>
> >
> > Signed-off-by: Dimitri Sivanich <sivanich@....com>
> > ---
> > arch/x86/kernel/apic/io_apic.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > Index: linux/arch/x86/kernel/apic/io_apic.c
> > ===================================================================
> > --- linux.orig/arch/x86/kernel/apic/io_apic.c
> > +++ linux/arch/x86/kernel/apic/io_apic.c
> > @@ -2478,9 +2478,12 @@ asmlinkage void smp_irq_move_cleanup_int
> > if (!desc)
> > continue;
> >
> > - cfg = irq_cfg(irq);
> > raw_spin_lock(&desc->lock);
> >
> > + cfg = irq_cfg(irq);
> > + if (!cfg)
> > + goto unlock;
> > +
> > /*
> > * Check if the irq migration is in progress. If so, we
> > * haven't received the cleanup request yet for this irq.
>
--
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