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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: 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>
This commit is contained in:
Rafael J. Wysocki 2013-08-13 02:39:30 +02:00 committed by Greg Kroah-Hartman
parent 910f5c7cdb
commit c7991b0b72
1 changed files with 5 additions and 1 deletions
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6
drivers/base/cpu.c
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@ -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;
}