compiler-rt/test/tsan/Darwin/fork_deadlock.cpp

   1 // TODO(#96597): fix and reenable
   2 // UNSUPPORTED: darwin
   3
   4 // RUN: %clangxx_tsan -O1 %s -o %t && %env_tsan_opts=atexit_sleep_ms=0 %run %t 2>&1 | FileCheck %s
   5
   6 // This test models what happens on Mac when fork
   7 // calls malloc/free inside of our atfork callbacks.
   8 // and ensures that we don't deadlock on malloc/free calls.
   9
  10 #include "../test.h"
  11 #include "syscall.h"
  12 #include <errno.h>
  13 #include <string.h>
  14 #include <sys/types.h>
  15 #include <sys/wait.h>
  16
  17 // disable_sanitizer_instrumentation on __tsan_test_only_on_fork is not
  18 // transitive, so we must apply it here as well.
  19 // Instrumenting alloc_free_blocks() will result in deadlocks in TSan.
  20 __attribute__((disable_sanitizer_instrumentation)) void alloc_free_blocks() {
  21   // Allocate a bunch of blocks to drain local allocator cache
  22   // and provoke it to lock allocator global mutexes.
  23   const int kBlocks = 1000;
  24   void *blocks[kBlocks];
  25   for (int i = 0; i < kBlocks; i++) {
  26     void *p = malloc(10);
  27     *(volatile char *)p = 0;
  28     blocks[i] = p;
  29   }
  30   for (int i = 0; i < kBlocks; i++)
  31     free(blocks[i]);
  32 }
  33
  34 __attribute__((disable_sanitizer_instrumentation)) extern "C" void
  35 __tsan_test_only_on_fork() {
  36   const char *msg = "__tsan_test_only_on_fork\n";
  37   write(2, msg, strlen(msg));
  38   alloc_free_blocks();
  39 }
  40
  41 static void *background(void *p) {
  42   for (;;)
  43     alloc_free_blocks();
  44   return 0;
  45 }
  46
  47 int main() {
  48   pthread_t th;
  49   pthread_create(&th, 0, background, 0);
  50   pthread_detach(th);
  51   for (int i = 0; i < 10; i++) {
  52     int pid = myfork();
  53     if (pid < 0) {
  54       fprintf(stderr, "failed to fork (%d)\n", errno);
  55       exit(1);
  56     }
  57     if (pid == 0) {
  58       // child
  59       exit(0);
  60     }
  61     // parent
  62     while (wait(0) < 0) {
  63     }
  64   }
  65   fprintf(stderr, "DONE\n");
  66 }
  67
  68 // CHECK: __tsan_test_only_on_fork
  69 // CHECK: DONE