[PATCH] cpu-hotplug: release `workqueue_mutex' properly on CPU hot-remove

_cpu_down() acquires `workqueue_mutex' on its process, but doen't release it
if __cpu_disable() fails.

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 27dd3ee..663c920 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -150,18 +150,18 @@ static int _cpu_down(unsigned int cpu)
        p = __stop_machine_run(take_cpu_down, NULL, cpu);
        mutex_unlock(&cpu_bitmask_lock);
 
-       if (IS_ERR(p)) {
+       if (IS_ERR(p) || cpu_online(cpu)) {
                /* CPU didn't die: tell everyone.  Can't complain. */
                if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
                                (void *)(long)cpu) == NOTIFY_BAD)
                        BUG();
 
-               err = PTR_ERR(p);
-               goto out_allowed;
-       }
-
-       if (cpu_online(cpu))
+               if (IS_ERR(p)) {
+                       err = PTR_ERR(p);
+                       goto out_allowed;
+               }
                goto out_thread;
+       }
 
        /* Wait for it to sleep (leaving idle task). */
        while (!idle_cpu(cpu))