Commit 14392fd3 authored Feb 07, 2011 by David Rientjes Committed by Ingo Molnar Feb 14, 2011

x86, numa: Add error handling for bad cpu-to-node mappings



CONFIG_DEBUG_PER_CPU_MAPS may return NUMA_NO_NODE when an
early_cpu_to_node() mapping hasn't been initialized.  In such a
case, it emits a warning and continues without an issue but
callers may try to use the return value to index into an array.

We can catch those errors and fail silently since a warning has
already been emitted.  No current user of numa_add_cpu()
requires this error checking to avoid a crash, but it's better
to be proactive in case a future user happens to have a bug and
a user tries to diagnose it with CONFIG_DEBUG_PER_CPU_MAPS.

Reported-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
LKML-Reference: <alpine.DEB.2.00.1102071407250.7812@chino.kir.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent b366801c

arch/x86/mm/numa.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -219,6 +219,10 @@ struct cpumask __cpuinit *debug_cpumask_set_cpu(int cpu, int enable)
		struct cpumask *mask;
		char buf[64];

		if (node == NUMA_NO_NODE) {
		/* early_cpu_to_node() already emits a warning and trace */
		return NULL;
		}
		mask = node_to_cpumask_map[node];
		if (!mask) {
		pr_err("node_to_cpumask_map[%i] NULL\n", node);

arch/x86/mm/numa_64.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -709,6 +709,10 @@ static void __cpuinit numa_set_cpumask(int cpu, int enable)
		struct cpumask *mask;
		int i;

		if (node == NUMA_NO_NODE) {
		/* early_cpu_to_node() already emits a warning and trace */
		return;
		}
		for_each_online_node(i) {
		unsigned long addr;

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