compiler-rt/test/dfsan/fork.cpp

   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 #include <assert.h>
  12 #include <errno.h>
  13 #include <pthread.h>
  14 #include <signal.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <sys/time.h>
  18 #include <sys/types.h>
  19 #include <sys/wait.h>
  20 #include <unistd.h>
  21
  22 #include <sanitizer/dfsan_interface.h>
  23
  24 int done;
  25
  26 void copy_labels_thread2() {
  27   volatile int x = 0;
  28   volatile int v = 0;
  29   dfsan_set_label(8, (void *)&x, sizeof(x));
  30   while (true) {
  31     v = x;
  32     x = v;
  33     if (__atomic_load_n(&done, __ATOMIC_RELAXED))
  34       return;
  35   }
  36 }
  37
  38 void copy_labels_thread1(int level) {
  39   if (!level)
  40     copy_labels_thread2();
  41   else
  42     copy_labels_thread1(level - 1);
  43 }
  44
  45 void *copy_labels_thread(void *id) {
  46   copy_labels_thread1((long)id);
  47   return 0;
  48 }
  49
  50 // Run through stackdepot in the child process.
  51 // If any of the hash table cells are locked, this may deadlock.
  52 void child() {
  53   volatile int x = 0;
  54   volatile int v = 0;
  55   dfsan_set_label(16, (void *)&x, sizeof(x));
  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_labels_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     }
  76   } else {
  77     // child
  78     child();
  79   }
  80 }
  81
  82 int main() {
  83   const int kChildren = 20;
  84   for (int i = 0; i < kChildren; ++i) {
  85     pid_t pid = fork();
  86     assert(dfsan_get_label(pid) == 0);
  87     if (pid) {
  88       // parent
  89     } else {
  90       test();
  91       exit(0);
  92     }
  93   }
  94
  95   for (int i = 0; i < kChildren; ++i) {
  96     pid_t p;
  97     while ((p = wait(NULL)) == -1) {
  98     }
  99   }
 100
 101   return 0;
 102 }
 103
 104 // Expect 20 (== kChildren) "done" messages.
 105 // CHECK-COUNT-20: done