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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-08-13 04:39:30 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-13 04:43:49 +0400
commitc7991b0b720efa5e0a590f6359d36e09bd187b76 (patch)
treef601b37ad472f0818c06e18fd9fa5a4d40d702bd /drivers/base/cpu.c
parent910f5c7cdb1d4541997f01c17b731bdfe2e92eda (diff)
downloadlinux-c7991b0b720efa5e0a590f6359d36e09bd187b76.tar.xz
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>
Diffstat (limited to 'drivers/base/cpu.c')
-rw-r--r--drivers/base/cpu.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 4c358bc44c72..6bfaaca6955e 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -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;
}