add: if (!kernel_startup && !are_interrupts_enabled()) panic("mutex_lock: called with interrupts disabled for mutex %p, sem %#lx\n", mutex, mutex->sem);
context: mutex_lock(mutex *mutex){	thread_id me = thread_get_current_thread_id();	if (me == mutex->holder)		panic("mutex_lock failure: mutex %p acquired twice by thread 0x%lx\n", mutex, me);	acquire_sem(mutex->sem);	mutex->holder = me;}