Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix race in cpupri introduced by cpumask_var changes
  sched: Fix latencytop and sleep profiling vs group scheduling

2 files changed, 33 insertions, 14 deletions

diff --git a/kernel/sched_cpupri.c b/kernel/sched_cpupri.c
index e6c251790dde..d014efbf947a 100644
--- a/kernel/sched_cpupri.c
+++ b/kernel/sched_cpupri.c
@@ -81,8 +81,21 @@ int cpupri_find(struct cpupri *cp, struct task_struct *p,
                 if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)
                         continue;
 
-                if (lowest_mask)
+                if (lowest_mask) {
                         cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);
+
+                        /*
+                         * We have to ensure that we have at least one bit
+                         * still set in the array, since the map could have
+                         * been concurrently emptied between the first and
+                         * second reads of vec->mask.  If we hit this
+                         * condition, simply act as though we never hit this
+                         * priority level and continue on.
+                         */
+                        if (cpumask_any(lowest_mask) >= nr_cpu_ids)
+                                continue;
+                }
+
                 return 1;
         }
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 9ffb2b2ceba4..652e8bdef9aa 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -611,9 +611,13 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 #ifdef CONFIG_SCHEDSTATS
+        struct task_struct *tsk = NULL;
+
+        if (entity_is_task(se))
+                tsk = task_of(se);
+
         if (se->sleep_start) {
                 u64 delta = rq_of(cfs_rq)->clock - se->sleep_start;
-                struct task_struct *tsk = task_of(se);
 
                 if ((s64)delta < 0)
                         delta = 0;
@@ -624,11 +628,11 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
                 se->sleep_start = 0;
                 se->sum_sleep_runtime += delta;
 
-                account_scheduler_latency(tsk, delta >> 10, 1);
+                if (tsk)
+                        account_scheduler_latency(tsk, delta >> 10, 1);
         }
         if (se->block_start) {
                 u64 delta = rq_of(cfs_rq)->clock - se->block_start;
-                struct task_struct *tsk = task_of(se);
 
                 if ((s64)delta < 0)
                         delta = 0;
@@ -639,17 +643,19 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
                 se->block_start = 0;
                 se->sum_sleep_runtime += delta;
 
-                /*
-                 * Blocking time is in units of nanosecs, so shift by 20 to
-                 * get a milliseconds-range estimation of the amount of
-                 * time that the task spent sleeping:
-                 */
-                if (unlikely(prof_on == SLEEP_PROFILING)) {
-
-                        profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk),
-                                     delta >> 20);
+                if (tsk) {
+                        /*
+                         * Blocking time is in units of nanosecs, so shift by
+                         * 20 to get a milliseconds-range estimation of the
+                         * amount of time that the task spent sleeping:
+                         */
+                        if (unlikely(prof_on == SLEEP_PROFILING)) {
+                                profile_hits(SLEEP_PROFILING,
+                                                (void *)get_wchan(tsk),
+                                                delta >> 20);
+                        }
+                        account_scheduler_latency(tsk, delta >> 10, 0);
                 }
-                account_scheduler_latency(tsk, delta >> 10, 0);
         }
 #endif
 }