1 files changed, 11 insertions, 1 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index a21f71af9d81..6b3a0c15144f 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -98,7 +98,8 @@ static inline void check_for_tasks(int cpu)
                      !cputime_eq(p->stime, cputime_zero)))
                         printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
                                 (state = %ld, flags = %x) \n",
-                                 p->comm, p->pid, cpu, p->state, p->flags);
+                                 p->comm, task_pid_nr(p), cpu,
+                                 p->state, p->flags);
         }
         write_unlock_irq(&tasklist_lock);
 }
@@ -264,6 +265,15 @@ out_notify:
 int __cpuinit cpu_up(unsigned int cpu)
 {
         int err = 0;
+        if (!cpu_isset(cpu, cpu_possible_map)) {
+                printk(KERN_ERR "can't online cpu %d because it is not "
+                        "configured as may-hotadd at boot time\n", cpu);
+#if defined(CONFIG_IA64) || defined(CONFIG_X86_64) || defined(CONFIG_S390)
+                printk(KERN_ERR "please check additional_cpus= boot "
+                                "parameter\n");
+#endif
+                return -EINVAL;
+        }
 
         mutex_lock(&cpu_add_remove_lock);
         if (cpu_hotplug_disabled)