From c7991b0b720efa5e0a590f6359d36e09bd187b76 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 13 Aug 2013 02:39:30 +0200 Subject: [PATCH] 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 Acked-by: Toshi Kani Signed-off-by: Greg Kroah-Hartman --- drivers/base/cpu.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) 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; }