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>hifive-unleashed-5.1
parent
910f5c7cdb
commit
c7991b0b72
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@ -43,11 +43,14 @@ static int __ref cpu_subsys_online(struct device *dev)
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struct cpu *cpu = container_of(dev, struct cpu, dev);
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struct cpu *cpu = container_of(dev, struct cpu, dev);
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int cpuid = dev->id;
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int cpuid = dev->id;
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int from_nid, to_nid;
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int from_nid, to_nid;
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int ret;
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int ret = -ENODEV;
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cpu_hotplug_driver_lock();
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cpu_hotplug_driver_lock();
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from_nid = cpu_to_node(cpuid);
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from_nid = cpu_to_node(cpuid);
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if (from_nid == NUMA_NO_NODE)
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goto out;
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ret = cpu_up(cpuid);
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ret = cpu_up(cpuid);
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/*
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/*
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* When hot adding memory to memoryless node and enabling a cpu
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* When hot adding memory to memoryless node and enabling a cpu
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@ -57,6 +60,7 @@ static int __ref cpu_subsys_online(struct device *dev)
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if (from_nid != to_nid)
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if (from_nid != to_nid)
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change_cpu_under_node(cpu, from_nid, to_nid);
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change_cpu_under_node(cpu, from_nid, to_nid);
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out:
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cpu_hotplug_driver_unlock();
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cpu_hotplug_driver_unlock();
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return ret;
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return ret;
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}
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}
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