From bae19fe033b0c5ed99b1ed27a4cce84625a24606 Mon Sep 17 00:00:00 2001 From: Andreas Herrmann Date: Wed, 14 Nov 2007 17:00:44 -0800 Subject: [PATCH] x86: don't call mce_create_device on CPU_UP_PREPARE Fix regression introduced with d435d862baca3e25e5eec236762a43251b1e7ffc ("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: Akinobu Mita Signed-off-by: Andreas Herrmann Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/kernel/cpu/mcheck/mce_64.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce_64.c b/arch/x86/kernel/cpu/mcheck/mce_64.c index b9f802e3520..447b351f1f2 100644 --- a/arch/x86/kernel/cpu/mcheck/mce_64.c +++ b/arch/x86/kernel/cpu/mcheck/mce_64.c @@ -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 = { -- 2.41.0