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 <sys/mman.h>
10 #include <sys/stat.h>
11 #include <stdio.h>
12 #include <pthread.h>
13 #include <string.h>
14 #include <stdlib.h>
15 #include <assert.h>
16 #include <setjmp.h>
17 #include <signal.h>
18 #include <fcntl.h>
19 #include <unistd.h>
20
21 static volatile char *lowest_j;
22 static jmp_buf goback;
23
sigsegv_handler(int signr)24 static void sigsegv_handler(int signr)
25 {
26 longjmp(goback, 1);
27 }
28
bad_things_till_guard_page(void)29 static void bad_things_till_guard_page(void)
30 {
31 fprintf(stderr, "... doing bad things till guard page\n");
32 char j = 0;
33 char *p = &j;
34
35 for (;;) {
36 j = j + *p;
37 p = p - 400;
38 lowest_j = p;
39 }
40 }
41
say_something(void)42 static void say_something(void)
43 {
44 fprintf(stderr, "plugh\n");
45 }
46
child_func(void * arg)47 static void* child_func ( void* arg )
48 {
49 if (setjmp(goback)) {
50 say_something();
51 } else
52 bad_things_till_guard_page();
53
54 return NULL;
55 }
56
main(int argc,const char ** argv)57 int main(int argc, const char** argv)
58 {
59 int r, fd;
60
61 /* We will discover the thread guard page using SEGV.
62 So, prepare an handler. */
63 struct sigaction sa;
64 sa.sa_handler = sigsegv_handler;
65 sigemptyset(&sa.sa_mask);
66 sa.sa_flags = 0;
67 if (sigaction (SIGSEGV, &sa, NULL) != 0)
68 perror("sigaction");
69
70 pthread_t child;
71
72 /* Create a file that will be used as stack for a pthread. */
73 const size_t file_size = 1024 * 1024;
74 const char file_name[] = "FILE";
75 fd = open(file_name, O_CREAT|O_WRONLY,
76 S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
77 assert(fd > 0);
78 void *p = malloc(file_size);
79 assert(p != 0);
80 memset(p, 0, file_size);
81 int written = write(fd, p, file_size);
82 assert(written == file_size);
83 close(fd);
84
85 /* Create a file-based stack for the child */
86 fd = open(file_name, O_CREAT|O_RDWR,
87 S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
88 assert(fd > 0);
89 const size_t stack_size = 256 * 1024;
90 assert(stack_size < file_size);
91 void *stack = mmap(NULL, stack_size, PROT_READ|PROT_WRITE,
92 MAP_PRIVATE, fd, 0);
93 assert(stack != (void *)-1);
94 pthread_attr_t attr;
95 pthread_attr_init(&attr);
96 r = pthread_attr_setstack(&attr, stack, stack_size);
97 assert(r == 0);
98
99 /* Create child run */
100 r = pthread_create(&child, &attr, child_func, NULL);
101 assert(r == 0);
102 r = pthread_join(child, NULL);
103 assert(r == 0);
104
105 /* Remove file */
106 unlink(file_name);
107 return 0;
108 }
109
110