compiler-rt/test/tsan/pthread_atfork_deadlock2.c

   1 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t | FileCheck %s
   2 // Regression test for
   3 // https://groups.google.com/d/msg/thread-sanitizer/e_zB9gYqFHM/DmAiTsrLAwAJ
   4 // pthread_atfork() callback triggers a data race and we deadlocked
   5 // on the report_mtx as we lock it around fork.
   6 #include "test.h"
   7 #include <sys/types.h>
   8 #include <sys/wait.h>
   9 #include <errno.h>
  10
  11 int glob = 0;
  12
  13 void *worker(void *unused) {
  14   glob++;
  15   barrier_wait(&barrier);
  16   return NULL;
  17 }
  18
  19 void atfork() {
  20   glob++;
  21 }
  22
  23 int main() {
  24   barrier_init(&barrier, 2);
  25   pthread_atfork(atfork, atfork, atfork);
  26   pthread_t t;
  27   pthread_create(&t, NULL, worker, NULL);
  28   barrier_wait(&barrier);
  29   pid_t pid = fork();
  30   if (pid < 0) {
  31     fprintf(stderr, "fork failed: %d\n", errno);
  32     return 1;
  33   }
  34   if (pid == 0) {
  35     fprintf(stderr, "CHILD\n");
  36     return 0;
  37   }
  38   if (pid != waitpid(pid, NULL, 0)) {
  39     fprintf(stderr, "waitpid failed: %d\n", errno);
  40     return 1;
  41   }
  42   pthread_join(t, NULL);
  43   fprintf(stderr, "PARENT\n");
  44   return 0;
  45 }
  46
  47 // CHECK: ThreadSanitizer: data race
  48 // CHECK:   Write of size 4
  49 // CHECK:     #0 atfork
  50 // CHECK:   Previous write of size 4
  51 // CHECK:     #0 worker
  52 // CHECK: CHILD
  53 // CHECK: PARENT