Merge branch 'urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile into perf/urgent

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index a3984f4ef192..f34b5b29fb95 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -141,6 +141,13 @@ static struct notifier_block module_load_nb = {
         .notifier_call = module_load_notify,
 };
 
+static void free_all_tasks(void)
+{
+        /* make sure we don't leak task structs */
+        process_task_mortuary();
+        process_task_mortuary();
+}
+
 int sync_start(void)
 {
         int err;
@@ -148,8 +155,6 @@ int sync_start(void)
         if (!zalloc_cpumask_var(&marked_cpus, GFP_KERNEL))
                 return -ENOMEM;
 
-        mutex_lock(&buffer_mutex);
-
         err = task_handoff_register(&task_free_nb);
         if (err)
                 goto out1;
@@ -166,7 +171,6 @@ int sync_start(void)
         start_cpu_work();
 
 out:
-        mutex_unlock(&buffer_mutex);
         return err;
 out4:
         profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
@@ -174,6 +178,7 @@ out3:
         profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
 out2:
         task_handoff_unregister(&task_free_nb);
+        free_all_tasks();
 out1:
         free_cpumask_var(marked_cpus);
         goto out;
@@ -182,20 +187,16 @@ out1:
 
 void sync_stop(void)
 {
-        /* flush buffers */
-        mutex_lock(&buffer_mutex);
         end_cpu_work();
         unregister_module_notifier(&module_load_nb);
         profile_event_unregister(PROFILE_MUNMAP, &munmap_nb);
         profile_event_unregister(PROFILE_TASK_EXIT, &task_exit_nb);
         task_handoff_unregister(&task_free_nb);
-        mutex_unlock(&buffer_mutex);
-        flush_cpu_work();
+        barrier();                      /* do all of the above first */
 
-        /* make sure we don't leak task structs */
-        process_task_mortuary();
-        process_task_mortuary();
+        flush_cpu_work();
 
+        free_all_tasks();
         free_cpumask_var(marked_cpus);
 }