cpu hotplug: mce: fix cpu hotplug error handling

- Clear kobject in percpu device_mce before calling sysdev_register() with

  Because mce_create_device() may fail and it leaves kobject filled with
  junk. It will be the problem when mce_create_device() will be called
  next time.

- Fix error handling in mce_create_device()

  Error handling should not do sysdev_remove_file() with not yet added
  attributes.

- Don't register hotcpu notifier when mce_create_device() returns error

- Do mce_create_device() in CPU_UP_PREPARE instead of CPU_ONLINE

Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Andi Kleen <ak@suse.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86/kernel/mce_64.c b/arch/x86/kernel/mce_64.c
index 8ca8f86..66e6b79 100644 (file)
--- a/arch/x86/kernel/mce_64.c
+++ b/arch/x86/kernel/mce_64.c
@@ -802,16 +802,29 @@ static __cpuinit int mce_create_device(unsigned int cpu)
        if (!mce_available(&cpu_data[cpu]))
                return -EIO;
 
+       memset(&per_cpu(device_mce, cpu).kobj, 0, sizeof(struct kobject));
        per_cpu(device_mce,cpu).id = cpu;
        per_cpu(device_mce,cpu).cls = &mce_sysclass;
 
        err = sysdev_register(&per_cpu(device_mce,cpu));
+       if (err)
+               return err;
+
+       for (i = 0; mce_attributes[i]; i++) {
+               err = sysdev_create_file(&per_cpu(device_mce,cpu),
+                                        mce_attributes[i]);
+               if (err)
+                       goto error;
+       }
 
-       if (!err) {
-               for (i = 0; mce_attributes[i]; i++)
-                       sysdev_create_file(&per_cpu(device_mce,cpu),
-                               mce_attributes[i]);
+       return 0;
+error:
+       while (i--) {
+               sysdev_remove_file(&per_cpu(device_mce,cpu),
+                                  mce_attributes[i]);
        }
+       sysdev_unregister(&per_cpu(device_mce,cpu));
+
        return err;
 }
 
@@ -823,7 +836,6 @@ static void mce_remove_device(unsigned int cpu)
                sysdev_remove_file(&per_cpu(device_mce,cpu),
                        mce_attributes[i]);
        sysdev_unregister(&per_cpu(device_mce,cpu));
-       memset(&per_cpu(device_mce, cpu).kobj, 0, sizeof(struct kobject));
 }
 
 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
@@ -831,18 +843,21 @@ 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_ONLINE:
-       case CPU_ONLINE_FROZEN:
-               mce_create_device(cpu);
+       case CPU_UP_PREPARE:
+       case CPU_UP_PREPARE_FROZEN:
+               err = 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 NOTIFY_OK;
+       return err ? NOTIFY_BAD : NOTIFY_OK;
 }
 
 static struct notifier_block mce_cpu_notifier = {
@@ -857,9 +872,13 @@ static __init int mce_init_device(void)
        if (!mce_available(&boot_cpu_data))
                return -EIO;
        err = sysdev_class_register(&mce_sysclass);
+       if (err)
+               return err;
 
        for_each_online_cpu(i) {
-               mce_create_device(i);
+               err = mce_create_device(i);
+               if (err)
+                       return err;
        }
 
        register_hotcpu_notifier(&mce_cpu_notifier);