Re: mm: Do not iterate over NR_CPUS in __zone_pcp_update()

From: KOSAKI Motohiro
Date: Tue Mar 09 2010 - 01:34:27 EST


> __zone_pcp_update() iterates over NR_CPUS instead of limiting the
> access to the possible cpus. This might result in access to
> uninitialized areas as the per cpu allocator only populates the per
> cpu memory for possible cpus.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
> mm/page_alloc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Looks good.
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>

>
> Index: linux-2.6/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.orig/mm/page_alloc.c
> +++ linux-2.6/mm/page_alloc.c
> @@ -3224,7 +3224,7 @@ static int __zone_pcp_update(void *data)
> int cpu;
> unsigned long batch = zone_batchsize(zone), flags;
>
> - for (cpu = 0; cpu < NR_CPUS; cpu++) {
> + for_each_possible_cpu(cpu) {
> struct per_cpu_pageset *pset;
> struct per_cpu_pages *pcp;
>
>
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