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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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|---|---|---|
| .. | ||
| Make.defs | ||
| pthread.h | ||
| pthread_barrierwait.c | ||
| pthread_cancel.c | ||
| pthread_completejoin.c | ||
| pthread_condbroadcast.c | ||
| pthread_condclockwait.c | ||
| pthread_condsignal.c | ||
| pthread_condwait.c | ||
| pthread_create.c | ||
| pthread_detach.c | ||
| pthread_exit.c | ||
| pthread_findjoininfo.c | ||
| pthread_getaffinity.c | ||
| pthread_getschedparam.c | ||
| pthread_initialize.c | ||
| pthread_join.c | ||
| pthread_mutex.c | ||
| pthread_mutexconsistent.c | ||
| pthread_mutexdestroy.c | ||
| pthread_mutexinconsistent.c | ||
| pthread_mutexinit.c | ||
| pthread_mutextimedlock.c | ||
| pthread_mutextrylock.c | ||
| pthread_mutexunlock.c | ||
| pthread_release.c | ||
| pthread_setaffinity.c | ||
| pthread_setschedparam.c | ||
| pthread_setschedprio.c | ||
| pthread_sigmask.c | ||