Thread 2: Probably a race condition: condition variable 0x........ has been signaled but the associated mutex 0x........ is not locked by the signalling thread. at 0x........: pthread_cond_signal (drd_pthread_intercepts.c:?) by 0x........: thread_func (pth_cond_race.c:?) by 0x........: vgDrd_thread_wrapper (drd_pthread_intercepts.c:?) cond 0x........ was first observed at: at 0x........: pthread_cond_init (drd_pthread_intercepts.c:?) by 0x........: main (pth_cond_race.c:?) mutex 0x........ was first observed at: at 0x........: pthread_mutex_init (drd_pthread_intercepts.c:?) by 0x........: main (pth_cond_race.c:?) ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)