From 6a2f47ca27fad36f99e8478a3807d4b8c7db80e7 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Fri, 27 Jun 2008 10:10:13 -0700 Subject: [PATCH] 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 Cc: Vegard Nossum Cc: "akpm@linux-foundation.org" Cc: Yinghai Lu Signed-off-by: Ingo Molnar --- arch/x86/kernel/setup_percpu.c | 26 +++++++++++++++++++++++--- include/asm-x86/topology.h | 7 ++++++- 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index 7068f95cccc6..43aca2de624a 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -346,6 +346,10 @@ int early_cpu_to_node(int cpu) 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 @@ cpumask_t *_node_to_cpumask_ptr(int node) 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 @@ cpumask_t node_to_cpumask(int node) 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 1f97758de4ab..98e5f17ea856 100644 --- a/include/asm-x86/topology.h +++ b/include/asm-x86/topology.h @@ -57,7 +57,12 @@ static inline int cpu_to_node(int cpu) } #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];