1 2 #include <pthread.h> 3 #include <stdio.h> 4 #include <stdlib.h> 5 #include <assert.h> 6 7 /* Test that locks, having entered the lock acquisition tracking 8 machinery, are forgotten by it when the client does 9 pthread_{mutex,rwlock}_destroy. 2008-Nov-10: see comments below. */ 10 11 int main ( void ) 12 { 13 int r; 14 pthread_mutex_t *mx1, *mx2; 15 assert (sizeof(pthread_mutex_t) <= 120); 16 mx1 = malloc(120 + sizeof(pthread_mutex_t) - sizeof(pthread_mutex_t)); 17 mx2 = malloc(120 + sizeof(pthread_mutex_t) - sizeof(pthread_mutex_t)); 18 19 assert(mx1); 20 assert(mx2); 21 22 r = pthread_mutex_init( mx1, NULL ); assert(r==0); 23 r = pthread_mutex_init( mx2, NULL ); assert(r==0); 24 25 /* Establish order 1 -> 2 */ 26 fprintf(stderr, "Establish order 1 -> 2\n"); 27 r = pthread_mutex_lock( mx1 ); assert(r==0); 28 r = pthread_mutex_lock( mx2 ); assert(r==0); 29 30 r = pthread_mutex_unlock( mx1 ); assert(r==0); 31 r = pthread_mutex_unlock( mx2 ); assert(r==0); 32 33 /* Try order 2 -> 1. This gives an error. */ 34 fprintf(stderr, "Try order 2 -> 1. This gives an error.\n"); 35 r = pthread_mutex_lock( mx2 ); assert(r==0); /* error */ 36 r = pthread_mutex_lock( mx1 ); assert(r==0); 37 38 r = pthread_mutex_unlock( mx1 ); assert(r==0); 39 r = pthread_mutex_unlock( mx2 ); assert(r==0); 40 41 /* De-initialise 2 and re-initialise it. This gives it a new 42 identity, so a second locking sequence 2 -> 1 should now be OK. */ 43 fprintf(stderr, 44 "Free 2 and re-allocate it. This gives it a new identity,\n"); 45 fprintf(stderr, "so a second locking sequence 2 -> 1 should now be OK.\n"); 46 pthread_mutex_destroy( mx2 ); 47 48 49 50 r = pthread_mutex_init( mx2, NULL ); assert(r==0); 51 52 r = pthread_mutex_lock( mx2 ); assert(r==0); 53 r = pthread_mutex_lock( mx1 ); assert(r==0); /* no error */ 54 55 r = pthread_mutex_unlock( mx1 ); assert(r==0); 56 r = pthread_mutex_unlock( mx2 ); assert(r==0); 57 58 /* done */ 59 60 fprintf(stderr, "done\n"); 61 r = pthread_mutex_destroy( mx1 ); 62 r = pthread_mutex_destroy( mx2 ); 63 64 free( mx1 ); 65 free( mx2 ); 66 67 return 0; 68 } 69 70 /* 2008-Nov-10: I believe this test is flawed and requires further 71 investigation. I don't think it really tests what it claims to 72 test. In particular, it still gives the right results if 73 "pthread_mutex_destroy( mx2 );" at line 46 is commented out. In 74 other words, laog somehow forgets about mx2 so that 2->1 lock 75 sequence at lines 52/3 does not produce a complaint, EVEN WHEN the 76 preceding "pthread_mutex_destroy( mx2 );" is not observed. I don't 77 know why this is, but it seems highly suspicious to me. */ 78
