Subject: Re: linux-next: Tree for June 5

From: Mike Travis <[email-masked]>
Date: Fri, 06 Jun 2008 08:52:46 -0700

Ingo Molnar wrote:
> * Vegard Nossum <[email-masked]> wrote:
> 
>>>> AFAICS this is not yet required for v2.6.26, as the requirement to 
>>>> never iterate to MAX_NUMNODES and call nr_cpus_node() with the 
>>>> index only got introduced by Mike's patch.
>>> the one below is needed as well i think.
>> Yeah. I think you had better take Mike's patches, I don't trust even 
>> that my patch and your fixlet does everything correctly.
> 
> yep, just discovered that we had them already ;-)
> 
> Thomas has just scripted up a new "detect if a commit is not in 
> linux-next yet" script that should avoid such problems in the future.
> 
> your second patch is still wanted, it would have detected the problem 
> earlier.
> 
> 	Ingo

Thanks, yes, I agree.  However I would like to modify it slightly:
---
Subject: [PATCH 1/1] x86: Add check for node passed to node_to_cpumask

  * When CONFIG_DEBUG_PER_CPU_MAPS is set, the node passed to
    node_to_cpumask and node_to_cpumask_ptr should be validated.

Signed-off-by: Mike Travis <[email-masked]>
---
 arch/x86/kernel/setup.c |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

--- linux-2.6.tip.orig/arch/x86/kernel/setup.c
+++ linux-2.6.tip/arch/x86/kernel/setup.c
@@ -399,6 +399,10 @@ int early_cpu_to_node(int cpu)
 	return per_cpu(x86_cpu_to_node_map, cpu);
 }
 
+
+/* empty cpumask */
+static cpumask_t cpu_mask_none;
+
 /*
  * Returns a pointer to the bitmask of CPUs on Node 'node'.
  */
@@ -411,6 +415,13 @@ cpumask_t *_node_to_cpumask_ptr(int node
 		dump_stack();
 		return &cpu_online_map;
 	}
+	if (node >= nr_node_ids) {
+		printk(KERN_WARNING
+			"_node_to_cpumask_ptr(%d): node > nr_node_ids(%d)\n",
+			node, nr_node_ids);
+		dump_stack();
+		return &cpu_mask_none;
+	}
 	return &node_to_cpumask_map[node];
 }
 EXPORT_SYMBOL(_node_to_cpumask_ptr);
@@ -426,6 +437,13 @@ cpumask_t node_to_cpumask(int node)
 		dump_stack();
 		return cpu_online_map;
 	}
+	if (node >= nr_node_ids) {
+		printk(KERN_WARNING
+			"node_to_cpumask(%d): node > nr_node_ids(%d)\n",
+			node, nr_node_ids);
+		dump_stack();
+		return cpu_mask_none;
+	}
 	return node_to_cpumask_map[node];
 }
 EXPORT_SYMBOL(node_to_cpumask);