[Bug 1836558] Re: Qemu-ppc Memory leak creating threads

[Laurent Vivier]

** Changed in: qemu
       Status: Confirmed => Fix Released

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Title:
  Qemu-ppc Memory leak creating threads

Status in QEMU:
  Fix Released

Bug description:
  When creating c++ threads (with c++ std::thread), the resulting binary
  has memory leaks when running with qemu-ppc.

  Eg the following c++ program, when compiled with gcc, consumes more
  and more memory while running at qemu-ppc. (does not have memory leaks
  when compiling for Intel, when running same binary on real powerpc CPU
  hardware also no memory leaks).

  (Note I used function getCurrentRSS to show available memory, see
  https://stackoverflow.com/questions/669438/how-to-get-memory-usage-at-
  runtime-using-c; calls commented out here)

  Compiler: powerpc-linux-gnu-g++ (Debian 8.3.0-2) 8.3.0 (but same problem with 
older g++ compilers even 4.9)
  Os: Debian 10.0 ( Buster) (but same problem seen on Debian 9/stetch)
  qemu: qemu-ppc version 3.1.50


  ---

  #include <iostream>
  #include <thread>
  #include <chrono>

  
  using namespace std::chrono_literals;

  // Create/run and join a 100 threads.
  void Fun100()
  {
  //    auto b4 = getCurrentRSS();
  //    std::cout << getCurrentRSS() << std::endl;
      for(int n = 0; n < 100; n++)
      {
          std::thread t([]
          {
              std::this_thread::sleep_for( 10ms );
          });
  //        std::cout << n << ' ' << getCurrentRSS() << std::endl;
          t.join();
      }
      std::this_thread::sleep_for( 500ms ); // to give OS some time to wipe 
memory...
  //    auto after = getCurrentRSS();
      std::cout << b4 << ' ' << after << std::endl;
  }

  
  int main(int, char **)
  {
      Fun100();
      Fun100();  // memory used keeps increasing
  }

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