1 files changed, 13 insertions, 23 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 7c4e2713df0a..677f25376a38 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -151,13 +151,13 @@ static inline void check_for_tasks(int cpu)
 
         write_lock_irq(&tasklist_lock);
         for_each_process(p) {
-                if (task_cpu(p) == cpu &&
+                if (task_cpu(p) == cpu && p->state == TASK_RUNNING &&
                     (!cputime_eq(p->utime, cputime_zero) ||
                      !cputime_eq(p->stime, cputime_zero)))
-                        printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
-                                (state = %ld, flags = %x) \n",
-                                 p->comm, task_pid_nr(p), cpu,
-                                 p->state, p->flags);
+                        printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d "
+                                "(state = %ld, flags = %x)\n",
+                                p->comm, task_pid_nr(p), cpu,
+                                p->state, p->flags);
         }
         write_unlock_irq(&tasklist_lock);
 }
@@ -209,9 +209,12 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
                 return -ENOMEM;
 
         cpu_hotplug_begin();
+        set_cpu_active(cpu, false);
         err = __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE | mod,
                                         hcpu, -1, &nr_calls);
         if (err == NOTIFY_BAD) {
+                set_cpu_active(cpu, true);
+
                 nr_calls--;
                 __raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
                                           hcpu, nr_calls, NULL);
@@ -223,11 +226,11 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 
         /* Ensure that we are not runnable on dying cpu */
         cpumask_copy(old_allowed, &current->cpus_allowed);
-        set_cpus_allowed_ptr(current,
-                             cpumask_of(cpumask_any_but(cpu_online_mask, cpu)));
+        set_cpus_allowed_ptr(current, cpu_active_mask);
 
         err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
         if (err) {
+                set_cpu_active(cpu, true);
                 /* CPU didn't die: tell everyone.  Can't complain. */
                 if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
                                             hcpu) == NOTIFY_BAD)
@@ -278,23 +281,8 @@ int __ref cpu_down(unsigned int cpu)
                 goto out;
         }
 
-        set_cpu_active(cpu, false);
-
-        /*
-         * Make sure the all cpus did the reschedule and are not
-         * using stale version of the cpu_active_mask.
-         * This is not strictly necessary becuase stop_machine()
-         * that we run down the line already provides the required
-         * synchronization. But it's really a side effect and we do not
-         * want to depend on the innards of the stop_machine here.
-         */
-        synchronize_sched();
-
         err = _cpu_down(cpu, 0);
 
-        if (cpu_online(cpu))
-                set_cpu_active(cpu, true);
-
 out:
         cpu_maps_update_done();
         stop_machine_destroy();
@@ -383,10 +371,12 @@ int disable_nonboot_cpus(void)
                 return error;
         cpu_maps_update_begin();
         first_cpu = cpumask_first(cpu_online_mask);
-        /* We take down all of the non-boot CPUs in one shot to avoid races
+        /*
+         * We take down all of the non-boot CPUs in one shot to avoid races
          * with the userspace trying to use the CPU hotplug at the same time
          */
         cpumask_clear(frozen_cpus);
+
         printk("Disabling non-boot CPUs ...\n");
         for_each_online_cpu(cpu) {
                 if (cpu == first_cpu)