On Saturday, August 17, 2013 01:46:57 PM Toshi Kani wrote:
> lock_device_hotplug() serializes CPU & Memory online/offline and hotplug
> operations. However, this lock is not held in the debug interfaces below
> that initiate CPU online/offline operations.
>
> - _debug_hotplug_cpu(), cpu0 hotplug test interface enabled by
> CONFIG_DEBUG_HOTPLUG_CPU0.
> - cpu_probe_store() and cpu_release_store(), cpu hotplug test interface
> enabled by CONFIG_ARCH_CPU_PROBE_RELEASE.
>
> This patch changes the above interfaces to hold lock_device_hotplug().
>
> Signed-off-by: Toshi Kani <toshi.k...@hp.com>
Acked-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> ---
> arch/x86/kernel/topology.c | 2 ++
> drivers/base/cpu.c | 16 ++++++++++++++--
> 2 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
> index 5823bbd..a3f35eb 100644
> --- a/arch/x86/kernel/topology.c
> +++ b/arch/x86/kernel/topology.c
> @@ -65,6 +65,7 @@ int __ref _debug_hotplug_cpu(int cpu, int action)
> if (!cpu_is_hotpluggable(cpu))
> return -EINVAL;
>
> + lock_device_hotplug();
> cpu_hotplug_driver_lock();
>
> switch (action) {
> @@ -91,6 +92,7 @@ int __ref _debug_hotplug_cpu(int cpu, int action)
> }
>
> cpu_hotplug_driver_unlock();
> + unlock_device_hotplug();
>
> return ret;
> }
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index 4c358bc..4cc6928 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -88,7 +88,13 @@ static ssize_t cpu_probe_store(struct device *dev,
> const char *buf,
> size_t count)
> {
> - return arch_cpu_probe(buf, count);
> + ssize_t ret;
> +
> + lock_device_hotplug();
> + ret = arch_cpu_probe(buf, count);
> + unlock_device_hotplug();
> +
> + return ret;
> }
>
> static ssize_t cpu_release_store(struct device *dev,
> @@ -96,7 +102,13 @@ static ssize_t cpu_release_store(struct device *dev,
> const char *buf,
> size_t count)
> {
> - return arch_cpu_release(buf, count);
> + ssize_t ret;
> +
> + lock_device_hotplug();
> + ret = arch_cpu_release(buf, count);
> + unlock_device_hotplug();
> +
> + return ret;
> }
>
> static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
> --
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--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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