5 files changed, 48 insertions, 26 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 295b7c756ca6..644ffbda17ca 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -247,6 +247,7 @@ extern void init_idle(struct task_struct *idle, int cpu);
 extern void init_idle_bootup_task(struct task_struct *idle);
 
 extern int runqueue_is_locked(void);
+extern void task_rq_unlock_wait(struct task_struct *p);
 
 extern cpumask_t nohz_cpu_mask;
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
diff --git a/kernel/exit.c b/kernel/exit.c
index 80137a5d9467..ae2b92be5fae 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -141,6 +141,11 @@ static void __exit_signal(struct task_struct *tsk)
         if (sig) {
                 flush_sigqueue(&sig->shared_pending);
                 taskstats_tgid_free(sig);
+                /*
+                 * Make sure ->signal can't go away under rq->lock,
+                 * see account_group_exec_runtime().
+                 */
+                task_rq_unlock_wait(tsk);
                 __cleanup_signal(sig);
         }
 }
diff --git a/kernel/sched.c b/kernel/sched.c
index 57c933ffbee1..50a21f964679 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -399,7 +399,7 @@ struct cfs_rq {
          */
         struct sched_entity *curr, *next, *last;
 
-        unsigned long nr_spread_over;
+        unsigned int nr_spread_over;
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
         struct rq *rq;  /* cpu runqueue to which this cfs_rq is attached */
@@ -969,6 +969,14 @@ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
         }
 }
 
+void task_rq_unlock_wait(struct task_struct *p)
+{
+        struct rq *rq = task_rq(p);
+
+        smp_mb(); /* spin-unlock-wait is not a full memory barrier */
+        spin_unlock_wait(&rq->lock);
+}
+
 static void __task_rq_unlock(struct rq *rq)
         __releases(rq->lock)
 {
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 5ae17762ec32..48ecc51e7701 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -144,7 +144,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
         last = __pick_last_entity(cfs_rq);
         if (last)
                 max_vruntime = last->vruntime;
-        min_vruntime = rq->cfs.min_vruntime;
+        min_vruntime = cfs_rq->min_vruntime;
         rq0_min_vruntime = per_cpu(runqueues, 0).cfs.min_vruntime;
         spin_unlock_irqrestore(&rq->lock, flags);
         SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", "MIN_vruntime",
@@ -161,26 +161,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
                         SPLIT_NS(spread0));
         SEQ_printf(m, "  .%-30s: %ld\n", "nr_running", cfs_rq->nr_running);
         SEQ_printf(m, "  .%-30s: %ld\n", "load", cfs_rq->load.weight);
-#ifdef CONFIG_SCHEDSTATS
-#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, rq->n);
-
-        P(yld_exp_empty);
-        P(yld_act_empty);
-        P(yld_both_empty);
-        P(yld_count);
 
-        P(sched_switch);
-        P(sched_count);
-        P(sched_goidle);
-
-        P(ttwu_count);
-        P(ttwu_local);
-
-        P(bkl_count);
-
-#undef P
-#endif
-        SEQ_printf(m, "  .%-30s: %ld\n", "nr_spread_over",
+        SEQ_printf(m, "  .%-30s: %d\n", "nr_spread_over",
                         cfs_rq->nr_spread_over);
 #ifdef CONFIG_FAIR_GROUP_SCHED
 #ifdef CONFIG_SMP
@@ -260,6 +242,25 @@ static void print_cpu(struct seq_file *m, int cpu)
 #undef P
 #undef PN
 
+#ifdef CONFIG_SCHEDSTATS
+#define P(n) SEQ_printf(m, "  .%-30s: %d\n", #n, rq->n);
+
+        P(yld_exp_empty);
+        P(yld_act_empty);
+        P(yld_both_empty);
+        P(yld_count);
+
+        P(sched_switch);
+        P(sched_count);
+        P(sched_goidle);
+
+        P(ttwu_count);
+        P(ttwu_local);
+
+        P(bkl_count);
+
+#undef P
+#endif
         print_cfs_stats(m, cpu);
         print_rt_stats(m, cpu);
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 51aa3e102acb..98345e45b059 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -716,6 +716,15 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
                 __enqueue_entity(cfs_rq, se);
 }
 
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+        if (cfs_rq->last == se)
+                cfs_rq->last = NULL;
+
+        if (cfs_rq->next == se)
+                cfs_rq->next = NULL;
+}
+
 static void
 dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 {
@@ -738,11 +747,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
 #endif
         }
 
-        if (cfs_rq->last == se)
-                cfs_rq->last = NULL;
-
-        if (cfs_rq->next == se)
-                cfs_rq->next = NULL;
+        clear_buddies(cfs_rq, se);
 
         if (se != cfs_rq->curr)
                 __dequeue_entity(cfs_rq, se);
@@ -977,6 +982,8 @@ static void yield_task_fair(struct rq *rq)
         if (unlikely(cfs_rq->nr_running == 1))
                 return;
 
+        clear_buddies(cfs_rq, se);
+
         if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) {
                 update_rq_clock(rq);
                 /*