Commit 87f1fb77 authored by Michal Koutný's avatar Michal Koutný Committed by Peter Zijlstra
Browse files

sched: Add RT_GROUP WARN checks for non-root task_groups 



With CONFIG_RT_GROUP_SCHED but runtime disabling of RT_GROUPs we expect
the existence of the root task_group only and all rt_sched_entity'ies
should be queued on root's rt_rq.

If we get a non-root RT_GROUP something went wrong.

Signed-off-by: default avatarMichal Koutný <mkoutny@suse.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250310170442.504716-9-mkoutny@suse.com
parent d6809c2f

kernel/sched/rt.c

+12 −2
Original line number Diff line number Diff line
@@ -176,11 +176,14 @@ static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) 


static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)

{

	/* Cannot fold with non-CONFIG_RT_GROUP_SCHED version, layout */

	WARN_ON(!rt_group_sched_enabled() && rt_rq->tg != &root_task_group);

	return rt_rq->rq;

}



static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)

{

	WARN_ON(!rt_group_sched_enabled() && rt_se->rt_rq->tg != &root_task_group);

	return rt_se->rt_rq;

}
@@ -188,6 +191,7 @@ static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se) 
{

	struct rt_rq *rt_rq = rt_se->rt_rq;



	WARN_ON(!rt_group_sched_enabled() && rt_rq->tg != &root_task_group);

	return rt_rq->rq;

}
@@ -504,8 +508,10 @@ typedef struct task_group *rt_rq_iter_t; 


static inline struct task_group *next_task_group(struct task_group *tg)

{

	if (!rt_group_sched_enabled())

	if (!rt_group_sched_enabled()) {

		WARN_ON(tg != &root_task_group);

		return NULL;

	}



	do {

		tg = list_entry_rcu(tg->list.next,
@@ -2607,8 +2613,9 @@ static int task_is_throttled_rt(struct task_struct *p, int cpu) 
{

	struct rt_rq *rt_rq;



#ifdef CONFIG_RT_GROUP_SCHED

#ifdef CONFIG_RT_GROUP_SCHED // XXX maybe add task_rt_rq(), see also sched_rt_period_rt_rq

	rt_rq = task_group(p)->rt_rq[cpu];

	WARN_ON(!rt_group_sched_enabled() && rt_rq->tg != &root_task_group);

#else

	rt_rq = &cpu_rq(cpu)->rt;

#endif
@@ -2718,6 +2725,9 @@ static int tg_rt_schedulable(struct task_group *tg, void *data) 
	    tg->rt_bandwidth.rt_runtime && tg_has_rt_tasks(tg))

		return -EBUSY;



	if (WARN_ON(!rt_group_sched_enabled() && tg != &root_task_group))

		return -EBUSY;



	total = to_ratio(period, runtime);



	/*