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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: Ingo Molnar <mingo@kernel.org>
Tested-by: Shrikanth 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
This commit is contained in:
Ingo Molnar 2025-03-17 11:42:52 +01:00
parent d047e32b8d
commit f7d2728cc0
8 changed files with 56 additions and 62 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
kernel/sched/core.c
View File

@ -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)

2
kernel/sched/core_sched.c
View File

@ -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);

12
kernel/sched/deadline.c
View File

@ -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

2
kernel/sched/ext.c
View File

@ -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

58
kernel/sched/fair.c
View File

@ -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 @@ done:
* 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 @@ next:
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 @@ unlock:
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);

2
kernel/sched/rt.c
View File

@ -1713,7 +1713,7 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rt_rq *rt_rq)
BUG_ON(idx >= MAX_RT_PRIO);
queue = array->queue + idx;
if (SCHED_WARN_ON(list_empty(queue)))
if (WARN_ON_ONCE(list_empty(queue)))
return NULL;
next = list_entry(queue->next, struct sched_rt_entity, run_list);

16
kernel/sched/sched.h
View File

@ -91,12 +91,6 @@ struct cpuidle_state;
#include "cpupri.h"
#include "cpudeadline.h"
#ifdef CONFIG_SCHED_DEBUG
# define SCHED_WARN_ON(x) WARN_ONCE(x, #x)
#else
# define SCHED_WARN_ON(x) ({ (void)(x), 0; })
#endif
/* task_struct::on_rq states: */
#define TASK_ON_RQ_QUEUED 1
#define TASK_ON_RQ_MIGRATING 2
@ -1571,7 +1565,7 @@ static inline void update_idle_core(struct rq *rq) { }
static inline struct task_struct *task_of(struct sched_entity *se)
{
SCHED_WARN_ON(!entity_is_task(se));
WARN_ON_ONCE(!entity_is_task(se));
return container_of(se, struct task_struct, se);
}
@ -1652,7 +1646,7 @@ static inline void assert_clock_updated(struct rq *rq)
* The only reason for not seeing a clock update since the
* last rq_pin_lock() is if we're currently skipping updates.
*/
SCHED_WARN_ON(rq->clock_update_flags < RQCF_ACT_SKIP);
WARN_ON_ONCE(rq->clock_update_flags < RQCF_ACT_SKIP);
}
static inline u64 rq_clock(struct rq *rq)
@ -1699,7 +1693,7 @@ static inline void rq_clock_cancel_skipupdate(struct rq *rq)
static inline void rq_clock_start_loop_update(struct rq *rq)
{
lockdep_assert_rq_held(rq);
SCHED_WARN_ON(rq->clock_update_flags & RQCF_ACT_SKIP);
WARN_ON_ONCE(rq->clock_update_flags & RQCF_ACT_SKIP);
rq->clock_update_flags |= RQCF_ACT_SKIP;
}
@ -1774,7 +1768,7 @@ static inline void rq_pin_lock(struct rq *rq, struct rq_flags *rf)
rq->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
rf->clock_update_flags = 0;
# ifdef CONFIG_SMP
SCHED_WARN_ON(rq->balance_callback && rq->balance_callback != &balance_push_callback);
WARN_ON_ONCE(rq->balance_callback && rq->balance_callback != &balance_push_callback);
# endif
#endif
}
@ -2685,7 +2679,7 @@ static inline void idle_set_state(struct rq *rq,
static inline struct cpuidle_state *idle_get_state(struct rq *rq)
{
SCHED_WARN_ON(!rcu_read_lock_held());
WARN_ON_ONCE(!rcu_read_lock_held());
return rq->idle_state;
}

2
kernel/sched/stats.h
View File

@ -144,7 +144,7 @@ static inline void psi_enqueue(struct task_struct *p, int flags)
if (p->se.sched_delayed) {
/* CPU migration of "sleeping" task */
SCHED_WARN_ON(!(flags & ENQUEUE_MIGRATED));
WARN_ON_ONCE(!(flags & ENQUEUE_MIGRATED));
if (p->in_memstall)
set |= TSK_MEMSTALL;
if (p->in_iowait)