diff --git a/include/cia-ld/tcb.h b/include/cia-ld/tcb.h
index 5eed95d..ac9d926 100644
--- a/include/cia-ld/tcb.h
+++ b/include/cia-ld/tcb.h
@@ -30,7 +30,7 @@ struct _LD_Thread_Block {
     /* +0x10 */ _Atomic(u32) thread_behaviour; /* One of the CIA_THREAD_BEHAVIOR_* constants */
     /* +0x14 */ _Atomic(i32) thread_finished;
     /* +0x18 */ u32 pad0;
-    /* +0x1c */ i32 exit_code;
+    /* +0x1c */ _Atomic(i32) exit_code;
     /* +0x20 */ u64 pad1;
     /* +0x28 */ u64 stack_canary;
 };
diff --git a/os/linux/tinyrt-threads.c b/os/linux/tinyrt-threads.c
index d16f83f..21bc468 100644
--- a/os/linux/tinyrt-threads.c
+++ b/os/linux/tinyrt-threads.c
@@ -65,7 +65,7 @@ void _rt_thread_finish(int exit_code) {
     }
     // If main thread set this thread to be joined, we signal it that we're done here
     if(thread_behaviour == _LD_THREAD_BEHAVIOUR_JOIN) {
-        tcb->exit_code = exit_code;
+        atomic_store_explicit(&tcb->exit_code, exit_code, memory_order_relaxed);
         atomic_store_explicit(&tcb->thread_finished, 1, memory_order_release);
         syscall(SYS_futex, &tcb->thread_finished, FUTEX_WAKE, 0, NULL, 0, 0);
         sys_exit(exit_code);
@@ -86,7 +86,7 @@ static _RT_Status _rt_thread_join(_RT_Thread *thread, int *out_exit_code) {
         syscall(SYS_futex, &tcb->thread_finished, FUTEX_WAIT, 0, NULL, 0, 0);
     }
     // Set the exit code
-    *out_exit_code = tcb->exit_code;
+    *out_exit_code = atomic_load_explicit(&tcb->exit_code, memory_order_acquire);
     return _RT_STATUS_OK;
 }
 
diff --git a/src/cia-sync/mutex.c b/src/cia-sync/mutex.c
index a065a57..2e4a646 100644
--- a/src/cia-sync/mutex.c
+++ b/src/cia-sync/mutex.c
@@ -10,20 +10,21 @@ void cia_mutex_init(Cia_Mutex *mutex) {
 void cia_mutex_lock(Cia_Mutex *mutex) {
     u32 p_tag;
     for(;;) {
-        //p_tag = __sync_val_compare_and_swap(&mutex->tag, _CIA_MUTEX_FREE, _CIA_MUTEX_LOCK);
         p_tag = _CIA_MUTEX_FREE;
         atomic_compare_exchange_strong_explicit(
             &mutex->tag
             , &p_tag
             , _CIA_MUTEX_LOCK
-            , memory_order_relaxed
+            , memory_order_acquire
             , memory_order_relaxed
         );
         // We got the mutex, lets bail
         if(p_tag == _CIA_MUTEX_FREE) {
             break;
         }
-#if 0
+#if 1
+        _rt_sync_wait(&mutex->tag, _CIA_MUTEX_LOCK, _RT_SYNC_WAIT_INFINITE);
+#else
         // We should wait if:
         //   (1) the mutex is contested
         //   (2) 
@@ -34,8 +35,6 @@ void cia_mutex_lock(Cia_Mutex *mutex) {
         if(should_wait) {
             _rt_sync_wait(&mutex->tag, _CIA_MUTEX_CONT, _RT_SYNC_WAIT_INFINITE);
         }
-#else
-        _rt_sync_wait(&mutex->tag, _CIA_MUTEX_LOCK, _RT_SYNC_WAIT_INFINITE);
 #endif
     }
 }
@@ -43,6 +42,6 @@ void cia_mutex_lock(Cia_Mutex *mutex) {
 void cia_mutex_unlock(Cia_Mutex *mutex) {
     // TODO: add error when we unlock a free mutex
     // TODO: support recursive muteces
-    atomic_store_explicit(&mutex->tag, _CIA_MUTEX_FREE, memory_order_relaxed);
+    atomic_store_explicit(&mutex->tag, _CIA_MUTEX_FREE, memory_order_release);
     _rt_sync_wake_one(&mutex->tag, NULL);
 }