Re: [PATCH] Fix NULL pointer for Xen guests

From: Prarit Bhargava
Date: Fri Apr 30 2010 - 18:02:40 EST




On 04/30/2010 04:55 PM, H. Peter Anvin wrote:
This looks like it should be tagged stable for 2.6.33. Is that correct?


Yes.

P.

-hpa

On 04/27/2010 08:24 AM, Prarit Bhargava wrote:
Upstream PV guests fail to boot because of a NULL pointer. It is possible that
xen guests have irq_desc->chip_data = NULL.

Test for NULL chip_data pointer before attempting to complete an irq move.

Signed-off-by: Prarit Bhargava<prarit@xxxxxxxxxx>
Acked-by: Suresh Siddha<suresh.b.siddha@xxxxxxxxx>

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 127b871..eb2789c 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2545,6 +2545,9 @@ void irq_force_complete_move(int irq)
struct irq_desc *desc = irq_to_desc(irq);
struct irq_cfg *cfg = desc->chip_data;

+ if (!cfg)
+ return;
+
__irq_complete_move(&desc, cfg->vector);
}
#else
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