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RDKBWIFI-348: Fix Race condition between timer tasks and scheduler execution #908

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Merged
gsathish86 merged 2 commits into from
Feb 17, 2026
Merged

RDKBWIFI-348: Fix Race condition between timer tasks and scheduler execution #908

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1805d40
RDKBWIFI-348: Fix Race condition between timer tasks and scheduler ex…
rakhilpe Feb 16, 2026
dd35746
Merge branch 'develop' into timer_schedule_fix
gsathish86 Feb 17, 2026
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8 changes: 6 additions & 2 deletions source/utils/scheduler.c
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Original file line number Diff line number Diff line change
Expand Up @@ -123,6 +123,7 @@ int scheduler_add_timer_task(struct scheduler *sched, bool high_prio, int *id,
unsigned int repetitions, bool start_immediately)
{
struct timer_task *tt;
struct timespec t_now;
struct
{
queue_t *timer_list;
Expand Down Expand Up @@ -150,6 +151,9 @@ int scheduler_add_timer_task(struct scheduler *sched, bool high_prio, int *id,

if (start_immediately) {
clock_gettime(CLOCK_MONOTONIC, &(tt->timeout));
} else {
clock_gettime(CLOCK_MONOTONIC, &t_now);
timespecadd(&t_now, &(tt->interval), &(tt->timeout));
}

pthread_mutex_lock(&sched->lock);
Expand Down Expand Up @@ -484,7 +488,7 @@ static int scheduler_calculate_timeout(struct scheduler *sched, struct timespec
printf("Error: **** Timer task expired again before previous execution to complete !!!\n");
}
tt->execute = timespecisset(&tt->timeout);
timespecadd(&t_now, &(tt->interval), &(tt->timeout));
timespecadd(&(tt->timeout), &(tt->interval), &(tt->timeout));
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Copilot AI Feb 16, 2026

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The timeout calculation has been changed from current-time-based to previous-timeout-based to maintain fixed intervals and prevent timing drift. This ensures timer tasks execute consistently even with small microsecond variations in scheduler timing.

However, be aware that if a timer task execution is significantly delayed (e.g., system suspension, heavy load, or long-running callbacks), the task may execute multiple times in quick succession to catch up to the intended schedule. Consider whether this catch-up behavior is appropriate for all use cases, and document it if it's intentional.

The same consideration applies to the high-priority task timeout calculation on line 501.

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}
}
for (i = 0; i < sched->num_hp_tasks; i++) {
Expand All @@ -494,7 +498,7 @@ static int scheduler_calculate_timeout(struct scheduler *sched, struct timespec
printf("Error: **** Timer task expired again before previous execution to complete (high priority) !!!\n");
}
tt->execute = timespecisset(&tt->timeout);
timespecadd(&t_now, &(tt->interval), &(tt->timeout));
timespecadd(&(tt->timeout), &(tt->interval), &(tt->timeout));
}
}
return 0;
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