2 files changed, 15 insertions, 12 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 3b159c5991b7..5447dc7defa9 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -273,6 +273,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
 
         setup_thread_stack(tsk, orig);
         clear_user_return_notifier(tsk);
+        clear_tsk_need_resched(tsk);
         stackend = end_of_stack(tsk);
         *stackend = STACK_END_MAGIC;    /* for overflow detection */
 
diff --git a/kernel/sched.c b/kernel/sched.c
index 6b7c26a1a097..da14302a9857 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -641,17 +641,18 @@ static void sched_irq_time_avg_update(struct rq *rq, u64 irq_time);
 
 inline void update_rq_clock(struct rq *rq)
 {
-        if (!rq->skip_clock_update) {
-                int cpu = cpu_of(rq);
-                u64 irq_time;
+        int cpu = cpu_of(rq);
+        u64 irq_time;
 
-                rq->clock = sched_clock_cpu(cpu);
-                irq_time = irq_time_cpu(cpu);
-                if (rq->clock - irq_time > rq->clock_task)
-                        rq->clock_task = rq->clock - irq_time;
+        if (rq->skip_clock_update)
+                return;
 
-                sched_irq_time_avg_update(rq, irq_time);
-        }
+        rq->clock = sched_clock_cpu(cpu);
+        irq_time = irq_time_cpu(cpu);
+        if (rq->clock - irq_time > rq->clock_task)
+                rq->clock_task = rq->clock - irq_time;
+
+        sched_irq_time_avg_update(rq, irq_time);
 }
 
 /*
@@ -2129,7 +2130,7 @@ static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
          * A queue event has occurred, and we're going to schedule.  In
          * this case, we can save a useless back to back clock update.
          */
-        if (test_tsk_need_resched(rq->curr))
+        if (rq->curr->se.on_rq && test_tsk_need_resched(rq->curr))
                 rq->skip_clock_update = 1;
 }
 
@@ -3973,7 +3974,6 @@ static void put_prev_task(struct rq *rq, struct task_struct *prev)
 {
         if (prev->se.on_rq)
                 update_rq_clock(rq);
-        rq->skip_clock_update = 0;
         prev->sched_class->put_prev_task(rq, prev);
 }
 
@@ -4031,7 +4031,6 @@ need_resched_nonpreemptible:
                 hrtick_clear(rq);
 
         raw_spin_lock_irq(&rq->lock);
-        clear_tsk_need_resched(prev);
 
         switch_count = &prev->nivcsw;
         if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
@@ -4063,6 +4062,8 @@ need_resched_nonpreemptible:
 
         put_prev_task(rq, prev);
         next = pick_next_task(rq);
+        clear_tsk_need_resched(prev);
+        rq->skip_clock_update = 0;
 
         if (likely(prev != next)) {
                 sched_info_switch(prev, next);
@@ -4071,6 +4072,7 @@ need_resched_nonpreemptible:
                 rq->nr_switches++;
                 rq->curr = next;
                 ++*switch_count;
+                WARN_ON_ONCE(test_tsk_need_resched(next));
 
                 context_switch(rq, prev, next); /* unlocks the rq */
                 /*