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Commit c7991b0b authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Greg Kroah-Hartman
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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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarToshi Kani <toshi.kani@hp.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 910f5c7c

drivers/base/cpu.c

+5 −1
Original line number Diff line number Diff line
@@ -43,11 +43,14 @@ static int __ref cpu_subsys_online(struct device *dev) 
	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 @@ static int __ref cpu_subsys_online(struct device *dev) 
	if (from_nid != to_nid)

		change_cpu_under_node(cpu, from_nid, to_nid);



 out:

	cpu_hotplug_driver_unlock();

	return ret;

}