2010-01-06 06:11:59

by Anton Blanchard

Subject: [patch 2/6] alpha: cpumask_of_node() should handle -1 as a node

pcibus_to_node can return -1 if we cannot determine which node a pci bus
is on. If passed -1, cpumask_of_node will negatively index the lookup array
and pull in random data:

# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpus
00000000,00000003,00000000,00000000
# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpulist
64-65

Change cpumask_of_node to check for -1 and return cpu_all_mask in this
case:

# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpus
ffffffff,ffffffff,ffffffff,ffffffff
# cat /sys/devices/pci0000:00/0000:00:01.0/local_cpulist
0-127

Signed-off-by: Anton Blanchard <[email protected]>
---

Index: linux-cpumask/arch/alpha/include/asm/topology.h
===================================================================
--- linux-cpumask.orig/arch/alpha/include/asm/topology.h 2010-01-06 15:20:22.952583839 +1100
+++ linux-cpumask/arch/alpha/include/asm/topology.h 2010-01-06 15:20:46.610083557 +1100
@@ -28,6 +28,9 @@ static const struct cpumask *cpumask_of_
{
int cpu;

+ if (node == -1)
+ return cpu_all_mask;
+
cpumask_clear(&node_to_cpumask_map[node]);

for_each_online_cpu(cpu) {

--

2010-01-14 18:24:20

by Matt Turner

Subject: Re: [patch 2/6] alpha: cpumask_of_node() should handle -1 as a node

On Tue, Jan 5, 2010 at 11:55 PM, Anton Blanchard <[email protected]> wrote:
> pcibus_to_node can return -1 if we cannot determine which node a pci bus
> is on. If passed -1, cpumask_of_node will negatively index the lookup array
> and pull in random data:
>
> # cat /sys/devices/pci0000:00/0000:00:01.0/local_cpus
> 00000000,00000003,00000000,00000000
> # cat /sys/devices/pci0000:00/0000:00:01.0/local_cpulist
> 64-65
>
> Change cpumask_of_node to check for -1 and return cpu_all_mask in this
> case:
>
> # cat /sys/devices/pci0000:00/0000:00:01.0/local_cpus
> ffffffff,ffffffff,ffffffff,ffffffff
> # cat /sys/devices/pci0000:00/0000:00:01.0/local_cpulist
> 0-127
>
> Signed-off-by: Anton Blanchard <[email protected]>
> ---
>
> Index: linux-cpumask/arch/alpha/include/asm/topology.h
> ===================================================================
> --- linux-cpumask.orig/arch/alpha/include/asm/topology.h ? ? ? ?2010-01-06 15:20:22.952583839 +1100
> +++ linux-cpumask/arch/alpha/include/asm/topology.h ? ? 2010-01-06 15:20:46.610083557 +1100
> @@ -28,6 +28,9 @@ static const struct cpumask *cpumask_of_
> ?{
> ? ? ? ?int cpu;
>
> + ? ? ? if (node == -1)
> + ? ? ? ? ? ? ? return cpu_all_mask;
> +
> ? ? ? ?cpumask_clear(&node_to_cpumask_map[node]);
>
> ? ? ? ?for_each_online_cpu(cpu) {
>
> --

Thanks! I've added this to alpha-2.6.

Matt