Re: [PATCH 2/2] Xen: Fix memory access violation bug when CONFIG_HAVE_SPARSE_IRQ is enabled

[Jeremy Fitzhardinge <jeremy@goop.org>]

Alex Nixon wrote:
> From: Alex Nixon <alex.nixon@citrix.com>
> Date: Mon, 18 Aug 2008 14:15:11 +0100
> Subject: [PATCH] Xen: Fix memory access violation bug when CONFIG_HAVE_SPARSE_IRQ is enabled
>
> When sparse IRQs are enabled, it is not safe to assume an IRQ descriptor exists for every possible IRQ.  This patch causes init_evtchn_cpu_bindings to skip initialisation of IRQ descriptors which don't exist.
>
> Signed-off-by: Alex Nixon <alex.nixon@citrix.com>
>   

Thanks again, Alex.

Ingo, please apply.

Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

> ---
>  drivers/xen/events.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/xen/events.c b/drivers/xen/events.c
> index 74dca12..6e7e765 100644
> --- a/drivers/xen/events.c
> +++ b/drivers/xen/events.c
> @@ -141,6 +141,8 @@ static void init_evtchn_cpu_bindings(void)
>  	/* By default all event channels notify CPU#0. */
>  	for (i = 0; i < nr_irqs; i++) {
>  		struct irq_desc *desc = to_irq_desc(i);
> +		if (!desc)
> +			continue;
>  		desc->affinity = cpumask_of_cpu(0);
>  	}
>  #endif
>