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-rw-r--r--arch/powerpc/mm/numa.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 30a42e24bf1..4ebbb9e9928 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1591,6 +1591,20 @@ int arch_update_cpu_topology(void)
cpu = cpu_last_thread_sibling(cpu);
}
+ /*
+ * In cases where we have nothing to update (because the updates list
+ * is too short or because the new topology is same as the old one),
+ * skip invoking update_cpu_topology() via stop-machine(). This is
+ * necessary (and not just a fast-path optimization) since stop-machine
+ * can end up electing a random CPU to run update_cpu_topology(), and
+ * thus trick us into setting up incorrect cpu-node mappings (since
+ * 'updates' is kzalloc()'ed).
+ *
+ * And for the similar reason, we will skip all the following updating.
+ */
+ if (!cpumask_weight(&updated_cpus))
+ goto out;
+
stop_machine(update_cpu_topology, &updates[0], &updated_cpus);
/*
@@ -1612,6 +1626,7 @@ int arch_update_cpu_topology(void)
changed = 1;
}
+out:
kfree(updates);
return changed;
}