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| // RUN: %clang_safestack %s -pthread -o %t
// RUN: %run %t 0
// RUN: not --crash %run %t 1
// Test unsafe stack deallocation. Unsafe stacks are not deallocated immediately
// at thread exit. They are deallocated by following exiting threads.
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
enum { kBufferSize = (1 << 15) };
void *start(void *ptr)
{
char buffer[kBufferSize];
return buffer;
}
int main(int argc, char **argv)
{
int arg = atoi(argv[1]);
pthread_t t1, t2;
char *t1_buffer = NULL;
if (pthread_create(&t1, NULL, start, NULL))
abort();
if (pthread_join(t1, &t1_buffer))
abort();
// Stack has not yet been deallocated
memset(t1_buffer, 0, kBufferSize);
if (arg == 0)
return 0;
for (int i = 0; i < 3; i++) {
if (pthread_create(&t2, NULL, start, NULL))
abort();
// Second thread destructor cleans up the first thread's stack.
if (pthread_join(t2, NULL))
abort();
// Should segfault here
memset(t1_buffer, 0, kBufferSize);
// PR39001: Re-try in the rare case that pthread_join() returns before the
// thread finishes exiting in the kernel--hence the tgkill() check for t1
// returns that it's alive despite pthread_join() returning.
sleep(1);
}
return 0;
}
|