Missing locking on sm->time_to_exit

Hi, developers, lock sm->thrd_lock is used to protect sm->time_to_exit. However, it only protects the write sm->time_to_exit = 1; not the read if (sm->time_to_exit). For mutually exclusive accesses, the locks should be guarding both places.

UnifyFS/server/src/unifyfs_service_manager.c

Lines 1478 to 1480 in 72808e1

    
           if (sm->time_to_exit) { 
        
               break;

UnifyFS/server/src/unifyfs_service_manager.c

Lines 252 to 255 in 72808e1

    
           pthread_mutex_lock(&(sm->thrd_lock)); 
        
           sm->time_to_exit = 1; 
        
           pthread_cond_signal(&(sm->thrd_cond)); 
        
           pthread_mutex_unlock(&(sm->thrd_lock));

This unlocked access to sm->time_to_exit is by design. The variable is initialized to 0, and once it is set to 1, the value will never change. It does not matter for correctness which loop iteration we detect the "time to exit" condition, only that we will eventually. The time window for "eventually" is around 50ms, which is plenty fast for this scenario when we are shutting down the server.

@MichaelBrim Thanks so much for your explanations.

	pthread_mutex_lock(&(sm->thrd_lock));
	sm->time_to_exit = 1;
	pthread_cond_signal(&(sm->thrd_cond));
	pthread_mutex_unlock(&(sm->thrd_lock));