x86: add check for node passed to node_to_cpumask, v3
* When CONFIG_DEBUG_PER_CPU_MAPS is set, the node passed to
node_to_cpumask and node_to_cpumask_ptr should be validated.
If invalid, then a dump_stack is performed and a zero cpumask
is returned.
v2: Slightly different version to remove a compiler warning.
v3: Redone to reflect moving setup.c -> setup_percpu.c
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index 7068f95..43aca2d 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -346,6 +346,10 @@
return per_cpu(x86_cpu_to_node_map, cpu);
}
+
+/* empty cpumask */
+static const cpumask_t cpu_mask_none;
+
/*
* Returns a pointer to the bitmask of CPUs on Node 'node'.
*/
@@ -358,13 +362,23 @@
dump_stack();
return &cpu_online_map;
}
- BUG_ON(node >= nr_node_ids);
- return &node_to_cpumask_map[node];
+ 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 (cpumask_t *)&cpu_mask_none;
+ }
+ return (cpumask_t *)&node_to_cpumask_map[node];
}
EXPORT_SYMBOL(_node_to_cpumask_ptr);
/*
* Returns a bitmask of CPUs on Node 'node'.
+ *
+ * Side note: this function creates the returned cpumask on the stack
+ * so with a high NR_CPUS count, excessive stack space is used. The
+ * node_to_cpumask_ptr function should be used whenever possible.
*/
cpumask_t node_to_cpumask(int node)
{
@@ -374,7 +388,13 @@
dump_stack();
return cpu_online_map;
}
- BUG_ON(node >= nr_node_ids);
+ 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);
diff --git a/include/asm-x86/topology.h b/include/asm-x86/topology.h
index 1f97758..98e5f17 100644
--- a/include/asm-x86/topology.h
+++ b/include/asm-x86/topology.h
@@ -57,7 +57,12 @@
}
#define early_cpu_to_node(cpu) cpu_to_node(cpu)
-/* Returns a bitmask of CPUs on Node 'node'. */
+/* Returns a bitmask of CPUs on Node 'node'.
+ *
+ * Side note: this function creates the returned cpumask on the stack
+ * so with a high NR_CPUS count, excessive stack space is used. The
+ * node_to_cpumask_ptr function should be used whenever possible.
+ */
static inline cpumask_t node_to_cpumask(int node)
{
return node_to_cpumask_map[node];