Merge branch 'perf/urgent' into perf/core

Merge reason: We are going to queue up a dependent patch.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 4 deletions

diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 2e48ec0c2e91..c21449f85a2a 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -119,15 +119,20 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
  * For preemptible RCU it is sufficient to call rcu_read_unlock in order
  * to exit the grace period. For classic RCU, a reschedule is required.
  */
-static void rcu_lock_break(struct task_struct *g, struct task_struct *t)
+static bool rcu_lock_break(struct task_struct *g, struct task_struct *t)
 {
+        bool can_cont;
+
         get_task_struct(g);
         get_task_struct(t);
         rcu_read_unlock();
         cond_resched();
         rcu_read_lock();
+        can_cont = pid_alive(g) && pid_alive(t);
         put_task_struct(t);
         put_task_struct(g);
+
+        return can_cont;
 }
 
 /*
@@ -154,9 +159,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
                         goto unlock;
                 if (!--batch_count) {
                         batch_count = HUNG_TASK_BATCHING;
-                        rcu_lock_break(g, t);
-                        /* Exit if t or g was unhashed during refresh. */
-                        if (t->state == TASK_DEAD || g->state == TASK_DEAD)
+                        if (!rcu_lock_break(g, t))
                                 goto unlock;
                 }
                 /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */