mutex_lock() will no longer panic() if acquire_sem() failed and the mutex

holder did not change (required for booting properly).
Also added a ToDo comment about a required mutex API change in order to
be able to return a status that indicates failure.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@10639 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kernel/core/lock.c

@@ -138,10 +138,13 @@ mutex_lock(mutex *mutex)
 	if (!kernel_startup && !are_interrupts_enabled())
 		panic("mutex_lock: called with interrupts disabled for mutex %p, sem %#lx\n", mutex, mutex->sem);
 
-	if (me == mutex->holder)
-		panic("mutex_lock failure: mutex %p (sem = 0x%lx) acquired twice by thread 0x%lx\n", mutex, mutex->sem, me);
+	// ToDo: if acquire_sem() fails, we shouldn't panic - but we should definitely
+	//	change the mutex API to actually return the status code
+	if (acquire_sem(mutex->sem) == B_OK) {
+		if (me == mutex->holder)
+			panic("mutex_lock failure: mutex %p (sem = 0x%lx) acquired twice by thread 0x%lx\n", mutex, mutex->sem, me);
+	}
 
-	acquire_sem(mutex->sem);
 	mutex->holder = me;
 }