Messages in this thread Patch in this message | | | Date | Mon, 21 May 2012 16:19:17 -0500 | From | Dimitri Sivanich <> | Subject | Re: [PATCH] x86: check for valid irq_cfg pointer in smp_irq_move_cleanup_interrupt |
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On Mon, May 21, 2012 at 11:07:04PM +0200, Thomas Gleixner wrote: > On Mon, 21 May 2012, 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. > > It seems that you either missed or failed to explain why it should be > done _after_ taking the lock. > > Changelogs matter, really. > How about this?
The smp_irq_move_cleanup_interrupt routine should be checking for a valid irq_cfg pointer prior to accessing it.
Follow the same protocol shown in irq_set_chip_data(), by taking the desc lock before accessing this location.
Signed-off-by: Dimitri Sivanich <sivanich@sgi.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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