Commit f7d2728c authored by Ingo Molnar's avatar Ingo Molnar
Browse files

sched/debug: Change SCHED_WARN_ON() to WARN_ON_ONCE() 



The scheduler has this special SCHED_WARN() facility that
depends on CONFIG_SCHED_DEBUG.

Since CONFIG_SCHED_DEBUG is getting removed, convert
SCHED_WARN() to WARN_ON_ONCE().

Note that the warning output isn't 100% equivalent:

   #define SCHED_WARN_ON(x)      WARN_ONCE(x, #x)

Because SCHED_WARN_ON() would output the 'x' condition
as well, while WARN_ONCE() will only show a backtrace.

Hopefully these are rare enough to not really matter.

If it does, we should probably introduce a new WARN_ON()
variant that outputs the condition in stringified form,
or improve WARN_ON() itself.

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Tested-by: default avatarShrikanth Hegde <sshegde@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250317104257.3496611-2-mingo@kernel.org
parent d047e32b

kernel/sched/core.c

+12 −12
Original line number Diff line number Diff line
@@ -801,7 +801,7 @@ void update_rq_clock(struct rq *rq) 


#ifdef CONFIG_SCHED_DEBUG

	if (sched_feat(WARN_DOUBLE_CLOCK))

		SCHED_WARN_ON(rq->clock_update_flags & RQCF_UPDATED);

		WARN_ON_ONCE(rq->clock_update_flags & RQCF_UPDATED);

	rq->clock_update_flags |= RQCF_UPDATED;

#endif

	clock = sched_clock_cpu(cpu_of(rq));
@@ -1719,7 +1719,7 @@ static inline void uclamp_rq_dec_id(struct rq *rq, struct task_struct *p, 


	bucket = &uc_rq->bucket[uc_se->bucket_id];



	SCHED_WARN_ON(!bucket->tasks);

	WARN_ON_ONCE(!bucket->tasks);

	if (likely(bucket->tasks))

		bucket->tasks--;
@@ -1739,7 +1739,7 @@ static inline void uclamp_rq_dec_id(struct rq *rq, struct task_struct *p, 
	 * Defensive programming: this should never happen. If it happens,

	 * e.g. due to future modification, warn and fix up the expected value.

	 */

	SCHED_WARN_ON(bucket->value > rq_clamp);

	WARN_ON_ONCE(bucket->value > rq_clamp);

	if (bucket->value >= rq_clamp) {

		bkt_clamp = uclamp_rq_max_value(rq, clamp_id, uc_se->value);

		uclamp_rq_set(rq, clamp_id, bkt_clamp);
@@ -2121,7 +2121,7 @@ void activate_task(struct rq *rq, struct task_struct *p, int flags) 


void deactivate_task(struct rq *rq, struct task_struct *p, int flags)

{

	SCHED_WARN_ON(flags & DEQUEUE_SLEEP);

	WARN_ON_ONCE(flags & DEQUEUE_SLEEP);



	WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);

	ASSERT_EXCLUSIVE_WRITER(p->on_rq);
@@ -2726,7 +2726,7 @@ __do_set_cpus_allowed(struct task_struct *p, struct affinity_context *ctx) 
	 * XXX do further audits, this smells like something putrid.

	 */

	if (ctx->flags & SCA_MIGRATE_DISABLE)

		SCHED_WARN_ON(!p->on_cpu);

		WARN_ON_ONCE(!p->on_cpu);

	else

		lockdep_assert_held(&p->pi_lock);
@@ -4195,7 +4195,7 @@ int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 
		 *  - we're serialized against set_special_state() by virtue of

		 *    it disabling IRQs (this allows not taking ->pi_lock).

		 */

		SCHED_WARN_ON(p->se.sched_delayed);

		WARN_ON_ONCE(p->se.sched_delayed);

		if (!ttwu_state_match(p, state, &success))

			goto out;
@@ -4489,7 +4489,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) 
	INIT_LIST_HEAD(&p->se.group_node);



	/* A delayed task cannot be in clone(). */

	SCHED_WARN_ON(p->se.sched_delayed);

	WARN_ON_ONCE(p->se.sched_delayed);



#ifdef CONFIG_FAIR_GROUP_SCHED

	p->se.cfs_rq			= NULL;
@@ -5745,7 +5745,7 @@ static void sched_tick_remote(struct work_struct *work) 
			 * we are always sure that there is no proxy (only a

			 * single task is running).

			 */

			SCHED_WARN_ON(rq->curr != rq->donor);

			WARN_ON_ONCE(rq->curr != rq->donor);

			update_rq_clock(rq);



			if (!is_idle_task(curr)) {
@@ -5965,7 +5965,7 @@ static inline void schedule_debug(struct task_struct *prev, bool preempt) 
		preempt_count_set(PREEMPT_DISABLED);

	}

	rcu_sleep_check();

	SCHED_WARN_ON(ct_state() == CT_STATE_USER);

	WARN_ON_ONCE(ct_state() == CT_STATE_USER);



	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
@@ -6811,7 +6811,7 @@ static inline void sched_submit_work(struct task_struct *tsk) 
	 * deadlock if the callback attempts to acquire a lock which is

	 * already acquired.

	 */

	SCHED_WARN_ON(current->__state & TASK_RTLOCK_WAIT);

	WARN_ON_ONCE(current->__state & TASK_RTLOCK_WAIT);



	/*

	 * If we are going to sleep and we have plugged IO queued,
@@ -9249,7 +9249,7 @@ static void cpu_util_update_eff(struct cgroup_subsys_state *css) 
	unsigned int clamps;



	lockdep_assert_held(&uclamp_mutex);

	SCHED_WARN_ON(!rcu_read_lock_held());

	WARN_ON_ONCE(!rcu_read_lock_held());



	css_for_each_descendant_pre(css, top_css) {

		uc_parent = css_tg(css)->parent
@@ -10584,7 +10584,7 @@ static void task_mm_cid_work(struct callback_head *work) 
	struct mm_struct *mm;

	int weight, cpu;



	SCHED_WARN_ON(t != container_of(work, struct task_struct, cid_work));

	WARN_ON_ONCE(t != container_of(work, struct task_struct, cid_work));



	work->next = work;	/* Prevent double-add */

	if (t->flags & PF_EXITING)

kernel/sched/core_sched.c

+1 −1
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ static unsigned long sched_core_update_cookie(struct task_struct *p, 
	 * a cookie until after we've removed it, we must have core scheduling

	 * enabled here.

	 */

	SCHED_WARN_ON((p->core_cookie || cookie) && !sched_core_enabled(rq));

	WARN_ON_ONCE((p->core_cookie || cookie) && !sched_core_enabled(rq));



	if (sched_core_enqueued(p))

		sched_core_dequeue(rq, p, DEQUEUE_SAVE);

kernel/sched/deadline.c

+6 −6
Original line number Diff line number Diff line
@@ -249,8 +249,8 @@ void __add_running_bw(u64 dl_bw, struct dl_rq *dl_rq) 


	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));

	dl_rq->running_bw += dl_bw;

	SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */

	SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);

	WARN_ON_ONCE(dl_rq->running_bw < old); /* overflow */

	WARN_ON_ONCE(dl_rq->running_bw > dl_rq->this_bw);

	/* kick cpufreq (see the comment in kernel/sched/sched.h). */

	cpufreq_update_util(rq_of_dl_rq(dl_rq), 0);

}
@@ -262,7 +262,7 @@ void __sub_running_bw(u64 dl_bw, struct dl_rq *dl_rq) 


	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));

	dl_rq->running_bw -= dl_bw;

	SCHED_WARN_ON(dl_rq->running_bw > old); /* underflow */

	WARN_ON_ONCE(dl_rq->running_bw > old); /* underflow */

	if (dl_rq->running_bw > old)

		dl_rq->running_bw = 0;

	/* kick cpufreq (see the comment in kernel/sched/sched.h). */
@@ -276,7 +276,7 @@ void __add_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) 


	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));

	dl_rq->this_bw += dl_bw;

	SCHED_WARN_ON(dl_rq->this_bw < old); /* overflow */

	WARN_ON_ONCE(dl_rq->this_bw < old); /* overflow */

}



static inline
@@ -286,10 +286,10 @@ void __sub_rq_bw(u64 dl_bw, struct dl_rq *dl_rq) 


	lockdep_assert_rq_held(rq_of_dl_rq(dl_rq));

	dl_rq->this_bw -= dl_bw;

	SCHED_WARN_ON(dl_rq->this_bw > old); /* underflow */

	WARN_ON_ONCE(dl_rq->this_bw > old); /* underflow */

	if (dl_rq->this_bw > old)

		dl_rq->this_bw = 0;

	SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);

	WARN_ON_ONCE(dl_rq->running_bw > dl_rq->this_bw);

}



static inline

kernel/sched/ext.c

+1 −1
Original line number Diff line number Diff line
@@ -2341,7 +2341,7 @@ static bool task_can_run_on_remote_rq(struct task_struct *p, struct rq *rq, 
{

	int cpu = cpu_of(rq);



	SCHED_WARN_ON(task_cpu(p) == cpu);

	WARN_ON_ONCE(task_cpu(p) == cpu);



	/*

	 * If @p has migration disabled, @p->cpus_ptr is updated to contain only

kernel/sched/fair.c

+29 −29
Original line number Diff line number Diff line
@@ -399,7 +399,7 @@ static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) 


static inline void assert_list_leaf_cfs_rq(struct rq *rq)

{

	SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list);

	WARN_ON_ONCE(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list);

}



/* Iterate through all leaf cfs_rq's on a runqueue */
@@ -696,7 +696,7 @@ static void update_entity_lag(struct cfs_rq *cfs_rq, struct sched_entity *se) 
{

	s64 vlag, limit;



	SCHED_WARN_ON(!se->on_rq);

	WARN_ON_ONCE(!se->on_rq);



	vlag = avg_vruntime(cfs_rq) - se->vruntime;

	limit = calc_delta_fair(max_t(u64, 2*se->slice, TICK_NSEC), se);
@@ -3317,7 +3317,7 @@ static void task_numa_work(struct callback_head *work) 
	bool vma_pids_skipped;

	bool vma_pids_forced = false;



	SCHED_WARN_ON(p != container_of(work, struct task_struct, numa_work));

	WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work));



	work->next = work;

	/*
@@ -4036,7 +4036,7 @@ static inline bool load_avg_is_decayed(struct sched_avg *sa) 
	 * Make sure that rounding and/or propagation of PELT values never

	 * break this.

	 */

	SCHED_WARN_ON(sa->load_avg ||

	WARN_ON_ONCE(sa->load_avg ||

		      sa->util_avg ||

		      sa->runnable_avg);
@@ -5460,7 +5460,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 
	clear_buddies(cfs_rq, se);



	if (flags & DEQUEUE_DELAYED) {

		SCHED_WARN_ON(!se->sched_delayed);

		WARN_ON_ONCE(!se->sched_delayed);

	} else {

		bool delay = sleep;

		/*
@@ -5470,7 +5470,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 
		if (flags & DEQUEUE_SPECIAL)

			delay = false;



		SCHED_WARN_ON(delay && se->sched_delayed);

		WARN_ON_ONCE(delay && se->sched_delayed);



		if (sched_feat(DELAY_DEQUEUE) && delay &&

		    !entity_eligible(cfs_rq, se)) {
@@ -5551,7 +5551,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) 
	}



	update_stats_curr_start(cfs_rq, se);

	SCHED_WARN_ON(cfs_rq->curr);

	WARN_ON_ONCE(cfs_rq->curr);

	cfs_rq->curr = se;



	/*
@@ -5592,7 +5592,7 @@ pick_next_entity(struct rq *rq, struct cfs_rq *cfs_rq) 
	if (sched_feat(PICK_BUDDY) &&

	    cfs_rq->next && entity_eligible(cfs_rq, cfs_rq->next)) {

		/* ->next will never be delayed */

		SCHED_WARN_ON(cfs_rq->next->sched_delayed);

		WARN_ON_ONCE(cfs_rq->next->sched_delayed);

		return cfs_rq->next;

	}
@@ -5628,7 +5628,7 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) 
		/* in !on_rq case, update occurred at dequeue */

		update_load_avg(cfs_rq, prev, 0);

	}

	SCHED_WARN_ON(cfs_rq->curr != prev);

	WARN_ON_ONCE(cfs_rq->curr != prev);

	cfs_rq->curr = NULL;

}
@@ -5851,7 +5851,7 @@ static int tg_unthrottle_up(struct task_group *tg, void *data) 


			cfs_rq->throttled_clock_self = 0;



			if (SCHED_WARN_ON((s64)delta < 0))

			if (WARN_ON_ONCE((s64)delta < 0))

				delta = 0;



			cfs_rq->throttled_clock_self_time += delta;
@@ -5871,7 +5871,7 @@ static int tg_throttle_down(struct task_group *tg, void *data) 
		cfs_rq->throttled_clock_pelt = rq_clock_pelt(rq);

		list_del_leaf_cfs_rq(cfs_rq);



		SCHED_WARN_ON(cfs_rq->throttled_clock_self);

		WARN_ON_ONCE(cfs_rq->throttled_clock_self);

		if (cfs_rq->nr_queued)

			cfs_rq->throttled_clock_self = rq_clock(rq);

	}
@@ -5980,7 +5980,7 @@ static bool throttle_cfs_rq(struct cfs_rq *cfs_rq) 
	 * throttled-list.  rq->lock protects completion.

	 */

	cfs_rq->throttled = 1;

	SCHED_WARN_ON(cfs_rq->throttled_clock);

	WARN_ON_ONCE(cfs_rq->throttled_clock);

	if (cfs_rq->nr_queued)

		cfs_rq->throttled_clock = rq_clock(rq);

	return true;
@@ -6136,7 +6136,7 @@ static inline void __unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq) 
	}



	/* Already enqueued */

	if (SCHED_WARN_ON(!list_empty(&cfs_rq->throttled_csd_list)))

	if (WARN_ON_ONCE(!list_empty(&cfs_rq->throttled_csd_list)))

		return;



	first = list_empty(&rq->cfsb_csd_list);
@@ -6155,7 +6155,7 @@ static void unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq) 
{

	lockdep_assert_rq_held(rq_of(cfs_rq));



	if (SCHED_WARN_ON(!cfs_rq_throttled(cfs_rq) ||

	if (WARN_ON_ONCE(!cfs_rq_throttled(cfs_rq) ||

	    cfs_rq->runtime_remaining <= 0))

		return;
@@ -6191,7 +6191,7 @@ static bool distribute_cfs_runtime(struct cfs_bandwidth *cfs_b) 
			goto next;



		/* By the above checks, this should never be true */

		SCHED_WARN_ON(cfs_rq->runtime_remaining > 0);

		WARN_ON_ONCE(cfs_rq->runtime_remaining > 0);



		raw_spin_lock(&cfs_b->lock);

		runtime = -cfs_rq->runtime_remaining + 1;
@@ -6212,7 +6212,7 @@ static bool distribute_cfs_runtime(struct cfs_bandwidth *cfs_b) 
				 * We currently only expect to be unthrottling

				 * a single cfs_rq locally.

				 */

				SCHED_WARN_ON(!list_empty(&local_unthrottle));

				WARN_ON_ONCE(!list_empty(&local_unthrottle));

				list_add_tail(&cfs_rq->throttled_csd_list,

					      &local_unthrottle);

			}
@@ -6237,7 +6237,7 @@ static bool distribute_cfs_runtime(struct cfs_bandwidth *cfs_b) 


		rq_unlock_irqrestore(rq, &rf);

	}

	SCHED_WARN_ON(!list_empty(&local_unthrottle));

	WARN_ON_ONCE(!list_empty(&local_unthrottle));



	rcu_read_unlock();
@@ -6789,7 +6789,7 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p) 
{

	struct sched_entity *se = &p->se;



	SCHED_WARN_ON(task_rq(p) != rq);

	WARN_ON_ONCE(task_rq(p) != rq);



	if (rq->cfs.h_nr_queued > 1) {

		u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
@@ -6900,8 +6900,8 @@ requeue_delayed_entity(struct sched_entity *se) 
	 * Because a delayed entity is one that is still on

	 * the runqueue competing until elegibility.

	 */

	SCHED_WARN_ON(!se->sched_delayed);

	SCHED_WARN_ON(!se->on_rq);

	WARN_ON_ONCE(!se->sched_delayed);

	WARN_ON_ONCE(!se->on_rq);



	if (sched_feat(DELAY_ZERO)) {

		update_entity_lag(cfs_rq, se);
@@ -7161,8 +7161,8 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags) 
		rq->next_balance = jiffies;



	if (p && task_delayed) {

		SCHED_WARN_ON(!task_sleep);

		SCHED_WARN_ON(p->on_rq != 1);

		WARN_ON_ONCE(!task_sleep);

		WARN_ON_ONCE(p->on_rq != 1);



		/* Fix-up what dequeue_task_fair() skipped */

		hrtick_update(rq);
@@ -8740,7 +8740,7 @@ static inline void set_task_max_allowed_capacity(struct task_struct *p) {} 
static void set_next_buddy(struct sched_entity *se)

{

	for_each_sched_entity(se) {

		if (SCHED_WARN_ON(!se->on_rq))

		if (WARN_ON_ONCE(!se->on_rq))

			return;

		if (se_is_idle(se))

			return;
@@ -12484,7 +12484,7 @@ static void set_cpu_sd_state_busy(int cpu) 


void nohz_balance_exit_idle(struct rq *rq)

{

	SCHED_WARN_ON(rq != this_rq());

	WARN_ON_ONCE(rq != this_rq());



	if (likely(!rq->nohz_tick_stopped))

		return;
@@ -12520,7 +12520,7 @@ void nohz_balance_enter_idle(int cpu) 
{

	struct rq *rq = cpu_rq(cpu);



	SCHED_WARN_ON(cpu != smp_processor_id());

	WARN_ON_ONCE(cpu != smp_processor_id());



	/* If this CPU is going down, then nothing needs to be done: */

	if (!cpu_active(cpu))
@@ -12603,7 +12603,7 @@ static void _nohz_idle_balance(struct rq *this_rq, unsigned int flags) 
	int balance_cpu;

	struct rq *rq;



	SCHED_WARN_ON((flags & NOHZ_KICK_MASK) == NOHZ_BALANCE_KICK);

	WARN_ON_ONCE((flags & NOHZ_KICK_MASK) == NOHZ_BALANCE_KICK);



	/*

	 * We assume there will be no idle load after this update and clear
@@ -13043,7 +13043,7 @@ bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b, 
	struct cfs_rq *cfs_rqb;

	s64 delta;



	SCHED_WARN_ON(task_rq(b)->core != rq->core);

	WARN_ON_ONCE(task_rq(b)->core != rq->core);



#ifdef CONFIG_FAIR_GROUP_SCHED

	/*
@@ -13246,7 +13246,7 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p) 


static void switched_to_fair(struct rq *rq, struct task_struct *p)

{

	SCHED_WARN_ON(p->se.sched_delayed);

	WARN_ON_ONCE(p->se.sched_delayed);



	attach_task_cfs_rq(p);
@@ -13281,7 +13281,7 @@ static void __set_next_task_fair(struct rq *rq, struct task_struct *p, bool firs 
	if (!first)

		return;



	SCHED_WARN_ON(se->sched_delayed);

	WARN_ON_ONCE(se->sched_delayed);



	if (hrtick_enabled_fair(rq))

		hrtick_start_fair(rq, p);