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ec145d5823
pthread_cond_wait() should be an atomic operation in the mutex lock/unlock.
Since the sched_lock() has been wrongly deleted in the previous commit,
the context switch will occurred after the mutex was unlocked:
--------------------------------------------------------------------
Task1(Priority 100) | Task2(Priority 101)
|
pthread_mutex_lock(mutex); |
| |
pthread_cond_wait(cond, mutex) |
| | |
| | |
| ->enter_critical_section() |
| ->pthread_mutex_give(mutex) | ----> pthread_mutex_lock(mutex); // contex switch to high priority task
| | pthread_cond_signal(cond); // signal before wait
| | <---- pthread_mutex_unlock(mutex); // switch back to original task
| ->pthread_sem_take(cond->sem)| // try to wait the signal, Deadlock.
| ->leave_critical_section() |
|
| ->pthread_mutex_take(mutex) |
| |
pthread_mutex_lock(mutex); |
---------------------------------------------------------------------
This PR will bring back sched_lock()/sched_unlock() to avoid context switch to ensure atomicity
Signed-off-by: chao an <anchao@xiaomi.com>
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|---|---|---|
| .. | ||
| addrenv | ||
| clock | ||
| environ | ||
| group | ||
| init | ||
| irq | ||
| misc | ||
| module | ||
| mqueue | ||
| paging | ||
| pthread | ||
| sched | ||
| semaphore | ||
| signal | ||
| task | ||
| timer | ||
| tls | ||
| wdog | ||
| wqueue | ||
| Kconfig | ||
| Makefile | ||