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newlib locks: Fix _lock_init() & _lock_init_recursive() failing to initialise a lock

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If scheduler was running, and lock was an automatic variable (ie stack-allocated) to be initialised by _lock_init*,
initialisation could be skipped if the lock variable was non-zero (and lock would be left invalid).

In other cases the lock is statically initialised to zero by __LOCK_INIT*
This commit is contained in:
Angus Gratton 2017-06-29 21:30:28 +10:00 committed by Angus Gratton
parent 9b955f4c9f
commit 75d6fdf73c
1 changed files with 10 additions and 2 deletions
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12
components/newlib/locks.c
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@ -41,14 +41,16 @@
static portMUX_TYPE lock_init_spinlock = portMUX_INITIALIZER_UNLOCKED;
/* Initialise the given lock by allocating a new mutex semaphore
/* Initialize the given lock by allocating a new mutex semaphore
as the _lock_t value.
Called by _lock_init*, also called by _lock_acquire* to lazily initialize locks that might have
been initialised (to zero only) before the RTOS scheduler started.
*/
static void IRAM_ATTR lock_init_generic(_lock_t *lock, uint8_t mutex_type) {
portENTER_CRITICAL(&lock_init_spinlock);
if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED) {
/* nothing to do until the scheduler is running */
*lock = 0; /* ensure lock is zeroed out, in case it's an automatic variable */
portEXIT_CRITICAL(&lock_init_spinlock);
return;
}
@ -84,10 +86,12 @@ static void IRAM_ATTR lock_init_generic(_lock_t *lock, uint8_t mutex_type) {
}
void IRAM_ATTR _lock_init(_lock_t *lock) {
*lock = 0; // In case lock's memory is uninitialized
lock_init_generic(lock, queueQUEUE_TYPE_MUTEX);
}
void IRAM_ATTR _lock_init_recursive(_lock_t *lock) {
*lock = 0; // In case lock's memory is uninitialized
lock_init_generic(lock, queueQUEUE_TYPE_RECURSIVE_MUTEX);
}
@ -96,6 +100,10 @@ void IRAM_ATTR _lock_init_recursive(_lock_t *lock) {
Note that FreeRTOS doesn't account for deleting mutexes while they
are held, and neither do we... so take care not to delete newlib
locks while they may be held by other tasks!
Also, deleting a lock in this way will cause it to be lazily
re-initialised if it is used again. Caller has to avoid doing
this!
*/
void IRAM_ATTR _lock_close(_lock_t *lock) {
portENTER_CRITICAL(&lock_init_spinlock);