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92a42be0 SL |
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_msan -std=c++11 -fsanitize-memory-track-origins=2 -g -O3 %s -o %t | |
6 | // RUN: MSAN_OPTIONS=store_context_size=1000,origin_history_size=0,origin_history_per_stack_limit=0 %run %t |& FileCheck %s | |
7 | ||
8 | // Fun fact: if test output is redirected to a file (as opposed to | |
9 | // being piped directly to FileCheck), we may lose some "done"s due to | |
10 | // a kernel bug: | |
11 | // https://lkml.org/lkml/2014/2/17/324 | |
12 | ||
13 | ||
14 | #include <pthread.h> | |
15 | #include <unistd.h> | |
16 | #include <stdio.h> | |
17 | #include <stdlib.h> | |
18 | #include <sys/types.h> | |
19 | #include <sys/wait.h> | |
20 | #include <sys/time.h> | |
21 | #include <signal.h> | |
22 | #include <errno.h> | |
23 | ||
24 | #include <sanitizer/msan_interface.h> | |
25 | ||
26 | int done; | |
27 | ||
28 | void copy_uninit_thread2() { | |
29 | volatile int x; | |
30 | volatile int v; | |
31 | while (true) { | |
32 | v = x; | |
33 | x = v; | |
34 | if (__atomic_load_n(&done, __ATOMIC_RELAXED)) | |
35 | return; | |
36 | } | |
37 | } | |
38 | ||
39 | void copy_uninit_thread1(int level) { | |
40 | if (!level) | |
41 | copy_uninit_thread2(); | |
42 | else | |
43 | copy_uninit_thread1(level - 1); | |
44 | } | |
45 | ||
46 | void *copy_uninit_thread(void *id) { | |
47 | copy_uninit_thread1((long)id); | |
48 | return 0; | |
49 | } | |
50 | ||
51 | // Run through stackdepot in the child process. | |
52 | // If any of the hash table cells are locked, this may deadlock. | |
53 | void child() { | |
54 | volatile int x; | |
55 | volatile int v; | |
56 | for (int i = 0; i < 10000; ++i) { | |
57 | v = x; | |
58 | x = v; | |
59 | } | |
60 | write(2, "done\n", 5); | |
61 | } | |
62 | ||
63 | void test() { | |
64 | const int kThreads = 10; | |
65 | pthread_t t[kThreads]; | |
66 | for (int i = 0; i < kThreads; ++i) | |
67 | pthread_create(&t[i], NULL, copy_uninit_thread, (void*)(long)i); | |
68 | usleep(100000); | |
69 | pid_t pid = fork(); | |
70 | if (pid) { | |
71 | // parent | |
72 | __atomic_store_n(&done, 1, __ATOMIC_RELAXED); | |
73 | pid_t p; | |
74 | while ((p = wait(NULL)) == -1) { } | |
75 | } else { | |
76 | // child | |
77 | child(); | |
78 | } | |
79 | } | |
80 | ||
81 | int main() { | |
82 | const int kChildren = 20; | |
83 | for (int i = 0; i < kChildren; ++i) { | |
84 | pid_t pid = fork(); | |
85 | if (pid) { | |
86 | // parent | |
87 | } else { | |
88 | test(); | |
89 | exit(0); | |
90 | } | |
91 | } | |
92 | ||
93 | for (int i = 0; i < kChildren; ++i) { | |
94 | pid_t p; | |
95 | while ((p = wait(NULL)) == -1) { } | |
96 | } | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | // Expect 20 (== kChildren) "done" messages. | |
102 | // CHECK: done | |
103 | // CHECK: done | |
104 | // CHECK: done | |
105 | // CHECK: done | |
106 | // CHECK: done | |
107 | // CHECK: done | |
108 | // CHECK: done | |
109 | // CHECK: done | |
110 | // CHECK: done | |
111 | // CHECK: done | |
112 | // CHECK: done | |
113 | // CHECK: done | |
114 | // CHECK: done | |
115 | // CHECK: done | |
116 | // CHECK: done | |
117 | // CHECK: done | |
118 | // CHECK: done | |
119 | // CHECK: done | |
120 | // CHECK: done | |
121 | // CHECK: done |