1 // Test that chained origins are fork-safe.
2 // Run a number of threads that create new chained origins, then fork
3 // and verify that origin reads do not deadlock in the child process.
4 //
5 // RUN: %clangxx_dfsan %s -o %t
6 // RUN: %run %t 2>&1 | FileCheck %s
7 //
8 // RUN: %clangxx_dfsan -mllvm -dfsan-track-origins=1 %s -o %t
9 // RUN: DFSAN_OPTIONS=store_context_size=1000,origin_history_size=0,origin_history_per_stack_limit=0 %run %t 2>&1 | FileCheck %s
10 //
11 // REQUIRES: x86_64-target-arch
12 
13 #include <assert.h>
14 #include <errno.h>
15 #include <pthread.h>
16 #include <signal.h>
17 #include <stdio.h>
18 #include <stdlib.h>
19 #include <sys/time.h>
20 #include <sys/types.h>
21 #include <sys/wait.h>
22 #include <unistd.h>
23 
24 #include <sanitizer/dfsan_interface.h>
25 
26 int done;
27 
28 void copy_labels_thread2() {
29   volatile int x = 0;
30   volatile int v = 0;
31   dfsan_set_label(8, (void *)&x, sizeof(x));
32   while (true) {
33     v = x;
34     x = v;
35     if (__atomic_load_n(&done, __ATOMIC_RELAXED))
36       return;
37   }
38 }
39 
40 void copy_labels_thread1(int level) {
41   if (!level)
42     copy_labels_thread2();
43   else
44     copy_labels_thread1(level - 1);
45 }
46 
47 void *copy_labels_thread(void *id) {
48   copy_labels_thread1((long)id);
49   return 0;
50 }
51 
52 // Run through stackdepot in the child process.
53 // If any of the hash table cells are locked, this may deadlock.
54 void child() {
55   volatile int x = 0;
56   volatile int v = 0;
57   dfsan_set_label(16, (void *)&x, sizeof(x));
58   for (int i = 0; i < 10000; ++i) {
59     v = x;
60     x = v;
61   }
62   write(2, "done\n", 5);
63 }
64 
65 void test() {
66   const int kThreads = 10;
67   pthread_t t[kThreads];
68   for (int i = 0; i < kThreads; ++i)
69     pthread_create(&t[i], NULL, copy_labels_thread, (void *)(long)i);
70   usleep(100000);
71   pid_t pid = fork();
72   if (pid) {
73     // parent
74     __atomic_store_n(&done, 1, __ATOMIC_RELAXED);
75     pid_t p;
76     while ((p = wait(NULL)) == -1) {
77     }
78   } else {
79     // child
80     child();
81   }
82 }
83 
84 int main() {
85   const int kChildren = 20;
86   for (int i = 0; i < kChildren; ++i) {
87     pid_t pid = fork();
88     assert(dfsan_get_label(pid) == 0);
89     if (pid) {
90       // parent
91     } else {
92       test();
93       exit(0);
94     }
95   }
96 
97   for (int i = 0; i < kChildren; ++i) {
98     pid_t p;
99     while ((p = wait(NULL)) == -1) {
100     }
101   }
102 
103   return 0;
104 }
105 
106 // Expect 20 (== kChildren) "done" messages.
107 // CHECK-COUNT-20: done
108