Commit bae19fe0 authored by Andreas Herrmann's avatar Andreas Herrmann Committed by Linus Torvalds
Browse files

x86: don't call mce_create_device on CPU_UP_PREPARE 



Fix regression introduced with d435d862
("cpu hotplug: mce: fix cpu hotplug error handling").

A CPU which was not brought up during boot (using maxcpus and
additional_cpus parameters) couldn't be onlined anymore.  For such a CPU it
seemed that MCE was not supported during CPU_UP_PREPARE-time which caused
mce_cpu_callback to return NOTIFY_BAD to notifier_call_chain.  To fix this
we:

 - call mce_create_device for CPU_ONLINE event (instead of CPU_UP_PREPARE),
 - avoid mce_remove_device() for the CPU that is not correctly initialized
   by mce_create_device() failure,
 - make mce_cpu_callback always return NOTIFY_OK for CPU_ONLINE event.
   Because CPU_ONLINE callback return value is always ignored.

[akinobu.mita@gmail.com: avoid mce_remove_device() for not initialized device]
[akinobu.mita@gmail.com: make mce_cpu_callback always return NOTIFY_OK]
Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: default avatarAndreas Herrmann <andreas.herrmann3@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 77f2878b

arch/x86/kernel/cpu/mcheck/mce_64.c

+11 −7
Original line number Diff line number Diff line
@@ -802,6 +802,8 @@ static struct sysdev_attribute *mce_attributes[] = { 
	NULL

};



static cpumask_t mce_device_initialized = CPU_MASK_NONE;



/* Per cpu sysdev init.  All of the cpus still share the same ctl bank */

static __cpuinit int mce_create_device(unsigned int cpu)

{
@@ -825,6 +827,7 @@ static __cpuinit int mce_create_device(unsigned int cpu) 
		if (err)

			goto error;

	}

	cpu_set(cpu, mce_device_initialized);



	return 0;

error:
@@ -841,10 +844,14 @@ static void mce_remove_device(unsigned int cpu) 
{

	int i;



	if (!cpu_isset(cpu, mce_device_initialized))

		return;



	for (i = 0; mce_attributes[i]; i++)

		sysdev_remove_file(&per_cpu(device_mce,cpu),

			mce_attributes[i]);

	sysdev_unregister(&per_cpu(device_mce,cpu));

	cpu_clear(cpu, mce_device_initialized);

}



/* Get notified when a cpu comes on/off. Be hotplug friendly. */
@@ -852,21 +859,18 @@ static int 
mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)

{

	unsigned int cpu = (unsigned long)hcpu;

	int err = 0;



	switch (action) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

		err = mce_create_device(cpu);

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		mce_create_device(cpu);

		break;

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		mce_remove_device(cpu);

		break;

	}

	return err ? NOTIFY_BAD : NOTIFY_OK;

	return NOTIFY_OK;

}



static struct notifier_block mce_cpu_notifier = {