1 /* This test causes an error in 3.10.1 and earlier versions like so:
2
3 ==8336== Can't extend stack to 0x4033f98 during signal delivery for thread 2:
4 ==8336== no stack segment
5
6 The reason was that only AnonC segments were considered as stack
7 segments. */
8
9 #include <assert.h>
10 #include <fcntl.h>
11 #include <pthread.h>
12 #include <setjmp.h>
13 #include <signal.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <unistd.h>
17 #include <sys/mman.h>
18 #include <sys/stat.h>
19
20 static volatile char *lowest_j;
21 static jmp_buf goback;
22
sigsegv_handler(int signr)23 static void sigsegv_handler(int signr)
24 {
25 longjmp(goback, 1);
26 }
27
bad_things_till_guard_page(void)28 static void bad_things_till_guard_page(void)
29 {
30 fprintf(stderr, "... doing bad things till guard page\n");
31 char j = 0;
32 char *p = &j;
33
34 for (;;) {
35 j = j + *p;
36 p = p - 400;
37 lowest_j = p;
38 }
39 }
40
say_something(void)41 static void say_something(void)
42 {
43 fprintf(stderr, "plugh\n");
44 }
45
child_func(void * arg)46 static void *child_func(void *arg)
47 {
48 if (setjmp(goback))
49 say_something();
50 else
51 bad_things_till_guard_page();
52
53 return NULL;
54 }
55
main(int argc,const char * argv[])56 int main(int argc, const char *argv[])
57 {
58 /* We will discover the thread guard page using SEGV.
59 So, prepare a handler. */
60 struct sigaction sa;
61 sa.sa_handler = sigsegv_handler;
62 sigemptyset(&sa.sa_mask);
63 sa.sa_flags = 0;
64 if (sigaction(SIGSEGV, &sa, NULL) != 0)
65 perror("sigaction");
66
67 /* Create a file that will be used as stack for a pthread. */
68 size_t file_size = 1024 * 1024;
69 const char file_name[] = "FILE";
70 int fd = open(file_name, O_CREAT|O_WRONLY,
71 S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
72 assert(fd >= 0);
73 void *p = calloc(file_size, 1);
74 assert(p != 0);
75 int written = write(fd, p, file_size);
76 assert(written == file_size);
77 close(fd);
78
79 /* Create a file-based stack for the child. */
80 fd = open(file_name, O_CREAT|O_RDWR,
81 S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
82 assert(fd >= 0);
83 const size_t stack_size = 256 * 1024;
84 assert(stack_size < file_size);
85 void *stack = mmap(NULL, stack_size, PROT_READ|PROT_WRITE,
86 MAP_PRIVATE, fd, 0);
87 assert(stack != (void *)-1);
88 pthread_attr_t attr;
89 pthread_attr_init(&attr);
90 int r = pthread_attr_setstack(&attr, stack, stack_size);
91 assert(r == 0);
92
93 /* Create child run. */
94 pthread_t child;
95 r = pthread_create(&child, &attr, child_func, NULL);
96 assert(r == 0);
97 r = pthread_join(child, NULL);
98 assert(r == 0);
99
100 /* Remove file */
101 unlink(file_name);
102 return 0;
103 }
104
105