compiler-rt/test/lsan/TestCases/Linux/libdl_deadlock.cpp

   1 // Regression test for a deadlock in leak detection,
   2 // where lsan would call dl_iterate_phdr while holding the allocator lock.
   3 // RUN: %clangxx_lsan %s -o %t && %run %t
   4
   5 #include <link.h>
   6 #include <mutex>
   7 #include <stdlib.h>
   8 #include <thread>
   9 #include <unistd.h>
  10
  11 std::mutex in, out;
  12
  13 int Callback(struct dl_phdr_info *info, size_t size, void *data) {
  14   for (int step = 0; step < 50; ++step) {
  15     void *p[1000];
  16     for (int i = 0; i < 1000; ++i)
  17       p[i] = malloc(10 * i);
  18
  19     if (step == 0)
  20       in.unlock();
  21
  22     for (int i = 0; i < 1000; ++i)
  23       free(p[i]);
  24   }
  25   out.unlock();
  26   return 1; // just once
  27 }
  28
  29 void Watchdog() {
  30   // This is just a fail-safe to turn a deadlock (in case the bug reappears)
  31   // into a (slow) test failure.
  32   usleep(40000000);
  33   if (!out.try_lock()) {
  34     write(2, "DEADLOCK\n", 9);
  35     exit(1);
  36   }
  37 }
  38
  39 int main() {
  40   in.lock();
  41   out.lock();
  42
  43   std::thread t([] { dl_iterate_phdr(Callback, nullptr); });
  44   t.detach();
  45
  46   std::thread w(Watchdog);
  47   w.detach();
  48
  49   // Wait for the malloc thread to preheat, then start leak detection (on exit)
  50   in.lock();
  51   return 0;
  52 }