helgrind/tests/tc09_bad_unlock.c

   1
   2 /* Check that an error is reported for various kinds of bogus
   3    pthread_mutex_unlock calls. */
   4
   5 #include <pthread.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8
   9 void* child_fn ( void* arg )
  10 {
  11    pthread_mutex_unlock( (pthread_mutex_t*)arg ); /* ERROR */
  12    return NULL;
  13 }
  14
  15 void nearly_main ( void )
  16 {
  17    pthread_t child;
  18    pthread_mutex_t mx1, mx2;
  19    int bogus[100], i;
  20    /* fill bogus with values which will cause glibc's pth_mx_unlock to fail */
  21    for (i = 0; i < 100; i++) bogus[i] = 0xFFFFFFFF;
  22    /* Unlocking a lock that is already unlocked */
  23    pthread_mutex_init( &mx1, NULL );
  24    pthread_mutex_lock( &mx1 );
  25    pthread_mutex_unlock( &mx1 );
  26
  27    pthread_mutex_unlock( &mx1 ); /* ERROR */
  28
  29    /* Unlocking a lock that is held by a different thread */
  30
  31    pthread_mutex_init( &mx2, NULL );
  32    pthread_mutex_lock( &mx2 );
  33    // start child and get it to unlock this lock
  34
  35    pthread_create( &child, NULL, child_fn, (void*)&mx2 );
  36       /* child runs and attempts to unlock our lock.  Error
  37          is reported in child_fn. */
  38    pthread_join(child, NULL );
  39
  40    /* Unlocking a totally bogus lock. */
  41    pthread_mutex_unlock( (pthread_mutex_t*) &bogus[50] ); /* ERROR */
  42
  43    /* Now we get a freeing-locked-lock error, since the stack
  44       frame is removed whilst mx2 is still locked. */
  45 }
  46
  47 int main ( void )
  48 {
  49    nearly_main(); fprintf(stderr, "---------------------\n" );
  50    nearly_main();
  51    return 0;
  52 }