driver core / cpu: Check if NUMA node is valid before bringing CPU up
There is a potential race condition between cpu_subsys_online()
and either acpi_processor_remove() or remove_memory() that execute
try_offline_node(). Namely, it is possible that cpu_subsys_online()
will run right after the CPUs NUMA node has been put offline and
cpu_to_node() executed by it will return NUMA_NO_NODE (-1). In
that case the CPU is gone and it doesn't make sense to call cpu_up()
for it, so make cpu_subsys_online() return -ENODEV then.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 4c358bc..6bfaaca 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -43,11 +43,14 @@
struct cpu *cpu = container_of(dev, struct cpu, dev);
int cpuid = dev->id;
int from_nid, to_nid;
- int ret;
+ int ret = -ENODEV;
cpu_hotplug_driver_lock();
from_nid = cpu_to_node(cpuid);
+ if (from_nid == NUMA_NO_NODE)
+ goto out;
+
ret = cpu_up(cpuid);
/*
* When hot adding memory to memoryless node and enabling a cpu
@@ -57,6 +60,7 @@
if (from_nid != to_nid)
change_cpu_under_node(cpu, from_nid, to_nid);
+ out:
cpu_hotplug_driver_unlock();
return ret;
}