From c0c2d8660f22fd5d5d834d7cdb6bb7e58a2af56c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Kijewski?= <rene.kijewski@fu-berlin.de>
Date: Thu, 1 Jan 2015 22:52:20 +0100
Subject: [PATCH] core: missing restoreIRQ in mutex_unlock
`mutex_unlock()` did not restore IRQsbefore yielding for the woken up
thread.
---
core/mutex.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/core/mutex.c b/core/mutex.c
index 7d8dcb5135..a2ab285a89 100644
--- a/core/mutex.c
+++ b/core/mutex.c
@@ -84,24 +84,30 @@ static void mutex_wait(struct mutex_t *mutex)
void mutex_unlock(struct mutex_t *mutex)
{
- DEBUG("%s: unlocking mutex. val: %u pid: %" PRIkernel_pid "\n", sched_active_thread->name, ATOMIC_VALUE(mutex->val), sched_active_pid);
unsigned irqstate = disableIRQ();
+ DEBUG("mutex_unlock(): val: %u pid: %" PRIkernel_pid "\n", mutex->val, sched_active_pid);
- if (ATOMIC_VALUE(mutex->val) != 0) {
- priority_queue_node_t *next = priority_queue_remove_head(&(mutex->queue));
- if (next) {
- tcb_t *process = (tcb_t *) next->data;
- DEBUG("%s: waking up waiter.\n", process->name);
- sched_set_status(process, STATUS_PENDING);
+ if (ATOMIC_VALUE(mutex->val) == 0) {
+ /* the mutex was not locked */
+ restoreIRQ(irqstate);
+ return;
+ }
- sched_switch(process->priority);
- }
- else {
- ATOMIC_VALUE(mutex->val) = 0; /* This is safe, interrupts are disabled */
- }
+ priority_queue_node_t *next = priority_queue_remove_head(&(mutex->queue));
+ if (!next) {
+ /* the mutex was locked and no thread was waiting for it */
+ ATOMIC_VALUE(mutex->val) = 0;
+ restoreIRQ(irqstate);
+ return;
}
+ tcb_t *process = (tcb_t *) next->data;
+ DEBUG("mutex_unlock: waking up waiting thread %" PRIkernel_pid "\n", process->pid);
+ sched_set_status(process, STATUS_PENDING);
+
+ uint16_t process_priority = process->priority;
restoreIRQ(irqstate);
+ sched_switch(process_priority);
}
void mutex_unlock_and_sleep(struct mutex_t *mutex)
--
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