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[pthread] Perform init_routine execution outside of the mutex

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The mutex is common across all the threads. It needn't be held across
the init_routine() call as long as the 'once' behaviour is guaranteed

Saw a deadlock case, where init_routine of one thread was waiting for
the completion of init_routine in another thread.

t2: wait for command
t1: pthread_once:
         lock once_mux
         init_routine:
               inform thread t2
               wait for signal from t2
t2: received command
         pthread_once
             lock once_mux (already held by t1)
---- Deadlock ----
This commit is contained in:
Kedar Sovani 2017-10-25 12:12:10 +05:30
parent 2765514314
commit 07992b08e8
1 changed files with 6 additions and 2 deletions
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8
components/pthread/pthread.c
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@ -347,6 +347,7 @@ int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
}
TaskHandle_t cur_task = xTaskGetCurrentTaskHandle();
uint8_t do_execute = 0;
// do not take mutex if OS is not running yet
if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED ||
// init_routine can call pthread_once for another objects, so use recursive mutex
@ -354,13 +355,16 @@ int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
!cur_task || xSemaphoreTakeRecursive(s_once_mux, portMAX_DELAY) == pdTRUE)
{
if (!once_control->init_executed) {
ESP_LOGV(TAG, "%s: call init_routine %p", __FUNCTION__, once_control);
init_routine();
do_execute = 1;
once_control->init_executed = 1;
}
if (cur_task) {
xSemaphoreGiveRecursive(s_once_mux);
}
if (do_execute) {
ESP_LOGV(TAG, "%s: call init_routine %p", __FUNCTION__, once_control);
init_routine();
}
}
else
{