Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes:

   - a deadline scheduler related bug fix which triggered a kernel
     warning

   - an RT_RUNTIME_SHARE fix

   - a stop_machine preemption fix

   - a potential NULL dereference fix in sched_domain_debug_one()"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt: Restore rt_runtime after disabling RT_RUNTIME_SHARE
  sched/deadline: Update rq_clock of later_rq when pushing a task
  stop_machine: Disable preemption after queueing stopper threads
  sched/topology: Check variable group before dereferencing it

4 files changed, 19 insertions, 3 deletions

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 10c7b51c0d1f..b5fbdde6afa9 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2090,8 +2090,14 @@ retry:
         sub_rq_bw(&next_task->dl, &rq->dl);
         set_task_cpu(next_task, later_rq->cpu);
         add_rq_bw(&next_task->dl, &later_rq->dl);
+
+        /*
+         * Update the later_rq clock here, because the clock is used
+         * by the cpufreq_update_util() inside __add_running_bw().
+         */
+        update_rq_clock(later_rq);
         add_running_bw(&next_task->dl, &later_rq->dl);
-        activate_task(later_rq, next_task, 0);
+        activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
         ret = 1;
 
         resched_curr(later_rq);
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 572567078b60..eaaec8364f96 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -836,6 +836,8 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
                  * can be time-consuming. Try to avoid it when possible.
                  */
                 raw_spin_lock(&rt_rq->rt_runtime_lock);
+                if (!sched_feat(RT_RUNTIME_SHARE) && rt_rq->rt_runtime != RUNTIME_INF)
+                        rt_rq->rt_runtime = rt_b->rt_runtime;
                 skip = !rt_rq->rt_time && !rt_rq->rt_nr_running;
                 raw_spin_unlock(&rt_rq->rt_runtime_lock);
                 if (skip)
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 05a831427bc7..56a0fed30c0a 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -47,7 +47,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
         if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
                 printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu);
         }
-        if (!cpumask_test_cpu(cpu, sched_group_span(group))) {
+        if (group && !cpumask_test_cpu(cpu, sched_group_span(group))) {
                 printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu);
         }
 
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 1ff523dae6e2..e190d1ef3a23 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -260,6 +260,15 @@ retry:
         err = 0;
         __cpu_stop_queue_work(stopper1, work1, &wakeq);
         __cpu_stop_queue_work(stopper2, work2, &wakeq);
+        /*
+         * The waking up of stopper threads has to happen
+         * in the same scheduling context as the queueing.
+         * Otherwise, there is a possibility of one of the
+         * above stoppers being woken up by another CPU,
+         * and preempting us. This will cause us to n ot
+         * wake up the other stopper forever.
+         */
+        preempt_disable();
 unlock:
         raw_spin_unlock(&stopper2->lock);
         raw_spin_unlock_irq(&stopper1->lock);
@@ -271,7 +280,6 @@ unlock:
         }
 
         if (!err) {
-                preempt_disable();
                 wake_up_q(&wakeq);
                 preempt_enable();
         }