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Commit 574b851e authored by Toshi Kani's avatar Toshi Kani Committed by Rafael J. Wysocki
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hotplug / x86: Add hotplug lock to missing places 



lock_device_hotplug[_sysfs]() 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: default avatarToshi Kani <toshi.kani@hp.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: default avatarYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent f6913f99

arch/x86/kernel/topology.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

}

drivers/base/cpu.c

+22 −2
Original line number Diff line number Diff line
@@ -93,7 +93,17 @@ static ssize_t cpu_probe_store(struct device *dev, 
			       const char *buf,

			       size_t count)

{

	return arch_cpu_probe(buf, count);

	ssize_t cnt;

	int ret;



	ret = lock_device_hotplug_sysfs();

	if (ret)

		return ret;



	cnt = arch_cpu_probe(buf, count);



	unlock_device_hotplug();

	return cnt;

}



static ssize_t cpu_release_store(struct device *dev,
@@ -101,7 +111,17 @@ static ssize_t cpu_release_store(struct device *dev, 
				 const char *buf,

				 size_t count)

{

	return arch_cpu_release(buf, count);

	ssize_t cnt;

	int ret;



	ret = lock_device_hotplug_sysfs();

	if (ret)

		return ret;



	cnt = arch_cpu_release(buf, count);



	unlock_device_hotplug();

	return cnt;

}



static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);