1 // Check that if LSan finds that SP doesn't point into thread stack (e.g.
2 // if swapcontext is used), LSan will not hit the guard page.
3 // RUN: %clang_lsan %s -o %t && %run %t
4 #include <errno.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <pthread.h>
9 #include <ucontext.h>
10 
11 pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
12 pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
13 int ctxfunc_started = 0;
14 
15 static void die(const char* msg, int err) {
16   if (err == 0)
17     err = errno;
18   fprintf(stderr, "%s: %s\n", msg, strerror(err));
19   exit(EXIT_FAILURE);
20 }
21 
22 static void ctxfunc() {
23   pthread_mutex_lock(&mutex);
24   ctxfunc_started = 1;
25   pthread_cond_signal(&cond);
26   pthread_mutex_unlock(&mutex);
27   // Leave this context alive when the program exits.
28   for (;;);
29 }
30 
31 static void* thread(void* arg) {
32   (void)arg;
33   ucontext_t ctx;
34   void* stack;
35 
36   if (getcontext(&ctx) < 0)
37     die("getcontext", 0);
38   stack = malloc(1 << 10);
39   if (stack == NULL)
40     die("malloc", 0);
41   ctx.uc_stack.ss_sp = stack;
42   ctx.uc_stack.ss_size = 1 << 10;
43   makecontext(&ctx, ctxfunc, 0);
44   setcontext(&ctx);
45   die("setcontext", 0);
46   return NULL;
47 }
48 
49 int main() {
50   pthread_t tid;
51   int i;
52 
53   pthread_mutex_lock(&mutex);
54   i = pthread_create(&tid, NULL, thread, NULL);
55   if (i != 0)
56     die("pthread_create", i);
57   while (!ctxfunc_started) pthread_cond_wait(&cond, &mutex);
58   pthread_mutex_unlock(&mutex);
59   return 0;
60 }
61