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-rw-r--r--kernel/sched/core.c28
1 files changed, 23 insertions, 5 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3d856c46f6d8..14afa518948c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2342,11 +2342,11 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
__sched_fork(clone_flags, p);
/*
- * We mark the process as running here. This guarantees that
+ * We mark the process as NEW here. This guarantees that
* nobody will actually run it, and a signal or other external
* event cannot wake it up and insert it on the runqueue either.
*/
- p->state = TASK_RUNNING;
+ p->state = TASK_NEW;
/*
* Make sure we do not leak PI boosting priority to the child.
@@ -2383,6 +2383,8 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
p->sched_class = &fair_sched_class;
}
+ init_entity_runnable_average(&p->se);
+
/*
* The child is not yet in the pid-hash so no cgroup attach races,
* and the cgroup is pinned to this child due to cgroup_fork()
@@ -2529,9 +2531,8 @@ void wake_up_new_task(struct task_struct *p)
struct rq_flags rf;
struct rq *rq;
- /* Initialize new task's runnable average */
- init_entity_runnable_average(&p->se);
raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
+ p->state = TASK_RUNNING;
#ifdef CONFIG_SMP
/*
* Fork balancing, do it here and not earlier because:
@@ -8237,6 +8238,7 @@ static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
{
struct task_struct *task;
struct cgroup_subsys_state *css;
+ int ret = 0;
cgroup_taskset_for_each(task, css, tset) {
#ifdef CONFIG_RT_GROUP_SCHED
@@ -8247,8 +8249,24 @@ static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
if (task->sched_class != &fair_sched_class)
return -EINVAL;
#endif
+ /*
+ * Serialize against wake_up_new_task() such that if its
+ * running, we're sure to observe its full state.
+ */
+ raw_spin_lock_irq(&task->pi_lock);
+ /*
+ * Avoid calling sched_move_task() before wake_up_new_task()
+ * has happened. This would lead to problems with PELT, due to
+ * move wanting to detach+attach while we're not attached yet.
+ */
+ if (task->state == TASK_NEW)
+ ret = -EINVAL;
+ raw_spin_unlock_irq(&task->pi_lock);
+
+ if (ret)
+ break;
}
- return 0;
+ return ret;
}
static void cpu_cgroup_attach(struct cgroup_taskset *tset)