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/** Cause a race inside code protected by a reader lock.
*/
/* Needed for older glibc's (2.3 and older, at least) who don't
otherwise "know" about pthread_rwlock_anything or about
PTHREAD_MUTEX_RECURSIVE (amongst things). */
#define _GNU_SOURCE 1
#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
static pthread_rwlock_t s_rwlock;
static int s_racy;
static void sleep_ms(const int ms)
{
struct timespec delay = { ms / 1000, (ms % 1000) * 1000 * 1000 };
nanosleep(&delay, 0);
}
static void* thread_func(void* arg)
{
pthread_rwlock_rdlock(&s_rwlock);
s_racy++;
pthread_rwlock_unlock(&s_rwlock);
sleep_ms(100);
return 0;
}
int main(int argc, char** argv)
{
pthread_t thread1;
pthread_t thread2;
#if 0
VALGRIND_DO_CLIENT_REQUEST_STMT(VG_USERREQ__DRD_TRACE_ADDR,
&s_racy, 0, 0, 0, 0);
#endif
pthread_rwlock_init(&s_rwlock, 0);
pthread_create(&thread1, 0, thread_func, 0);
pthread_create(&thread2, 0, thread_func, 0);
pthread_join(thread1, 0);
pthread_join(thread2, 0);
pthread_rwlock_destroy(&s_rwlock);
fprintf(stderr, "Result: %d\n", s_racy);
return 0;
}
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