compiler-rt/test/tsan/pthread_atfork_deadlock3.c

   1 // RUN: %clang_tsan -O1 %s -o %t && %deflake %run %t > %t.out
   2 // RUN: FileCheck %s --check-prefixes=CHECK,PARENT --input-file %t.out
   3 // RUN: FileCheck %s --check-prefixes=CHECK,CHILD --input-file %t.out
   4 // Regression test for
   5 // https://groups.google.com/g/thread-sanitizer/c/TQrr4-9PRYo/m/HFR4FMi6AQAJ
   6 #include "test.h"
   7 #include <errno.h>
   8 #include <signal.h>
   9 #include <string.h>
  10 #include <sys/types.h>
  11 #include <sys/wait.h>
  12
  13 long glob = 0;
  14
  15 void *worker(void *main) {
  16   glob++;
  17   // synchronize with main
  18   barrier_wait(&barrier);
  19   // synchronize with atfork
  20   barrier_wait(&barrier);
  21   pthread_kill((pthread_t)main, SIGPROF);
  22   barrier_wait(&barrier);
  23   // synchronize with afterfork
  24   barrier_wait(&barrier);
  25   pthread_kill((pthread_t)main, SIGPROF);
  26   barrier_wait(&barrier);
  27   return NULL;
  28 }
  29
  30 void atfork() {
  31   barrier_wait(&barrier);
  32   barrier_wait(&barrier);
  33   write(2, "in atfork\n", strlen("in atfork\n"));
  34   static volatile long a;
  35   __atomic_fetch_add(&a, 1, __ATOMIC_RELEASE);
  36 }
  37
  38 void afterfork() {
  39   barrier_wait(&barrier);
  40   barrier_wait(&barrier);
  41   write(2, "in afterfork\n", strlen("in afterfork\n"));
  42   static volatile long a;
  43   __atomic_fetch_add(&a, 1, __ATOMIC_RELEASE);
  44 }
  45
  46 void afterfork_child() {
  47   write(2, "in afterfork_child\n", strlen("in afterfork_child\n"));
  48   glob++;
  49 }
  50
  51 void handler(int sig) {
  52   write(2, "in handler\n", strlen("in handler\n"));
  53   glob++;
  54 }
  55
  56 int main() {
  57   barrier_init(&barrier, 2);
  58   struct sigaction act = {};
  59   act.sa_handler = &handler;
  60   if (sigaction(SIGPROF, &act, 0)) {
  61     perror("sigaction");
  62     exit(1);
  63   }
  64   pthread_atfork(atfork, afterfork, afterfork_child);
  65   pthread_t t;
  66   pthread_create(&t, NULL, worker, (void *)pthread_self());
  67   barrier_wait(&barrier);
  68   pid_t pid = fork();
  69   if (pid < 0) {
  70     fprintf(stderr, "fork failed: %d\n", errno);
  71     return 1;
  72   }
  73   if (pid == 0) {
  74     fprintf(stderr, "CHILD\n");
  75     return 0;
  76   }
  77   if (pid != waitpid(pid, NULL, 0)) {
  78     fprintf(stderr, "waitpid failed: %d\n", errno);
  79     return 1;
  80   }
  81   pthread_join(t, NULL);
  82   fprintf(stderr, "PARENT\n");
  83   return 0;
  84 }
  85
  86 // CHECK: in atfork
  87 // CHECK: in handler
  88 // CHECK: ThreadSanitizer: data race
  89 // CHECK:   Write of size 8
  90 // CHECK:     #0 handler
  91 // CHECK:   Previous write of size 8
  92 // CHECK:     #0 worker
  93 // PARENT: afterfork
  94 // PARENT: in handler
  95 // CHILD: afterfork_child
  96 // CHILD: CHILD
  97 // CHECK: PARENT