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"gzserver" received signal SIGSEGV, Segmentation fault

asked 2021-01-08 06:28:05 -0500

KASUYASU gravatar image

Thread 198 "gzserver" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7f933bbfe700 (LWP 25829)] 0x00007f95b7a81b74 in std::__atomic_base<bool>::load ( __m=std::memory_order_seq_cst, this=0x7f951c045d90) at /usr/include/c++/7/bits/atomic_base.h:396 396 return __atomic_load_n(&_M_i, __m); (gdb) bt

0 0x00007f95b7a81b74 in std::__atomic_base<bool>::load(std::memory_order) const (__m=std::memory_order_seq_cst, this=0x7f951c045d90)

at /usr/include/c++/7/bits/atomic_base.h:396

1 0x00007f95b7a81b74 in std::atomic<bool>::operator bool() const (this=0x7f951c045d90) at /usr/include/c++/7/atomic:86

2 0x00007f95b7a81b74 in gazebo::event::EventT<void (gazebo::common::updateinfo="" const&amp;)&gt;::signal<gazebo::common::updateinfo="">(gazebo::common::UpdateInfo const&) (_p=..., this=<optimized out="">)

at /home/***/gazebo-9.0.0/gazebo/common/Event.hh:291

3 0x00007f95b7a81b74 in gazebo::event::EventT<void (gazebo::common::updateinfo="" const&amp;)&gt;::operator()<gazebo::common::updateinfo="">(gazebo::common::UpdateInfo const&) (_p=..., this=<optimized out="">)

at /home/***/gazebo-9.0.0/gazebo/common/Event.hh:128

4 0x00007f95b7a81b74 in gazebo::physics::World::Update() (this=this@entry=0x55fc0b613190) at /home/*/gazebo-9.0.0/gazebo/physics/World.cc:767

5 0x00007f95b7a8cc6b in gazebo::physics::World::Step() (this=this@entry=0x55fc0b613190) at /home/*/gazebo-9.0.0/gazebo/physics/World.cc:696

6 0x00007f95b7a8d11d in gazebo::physics::World::RunLoop() (this=0x55fc0b613190) at /home/*/gazebo-9.0.0/gazebo/physics/World.cc:505

7 0x00007f95b89686df in () at /usr/lib/x86_64-linux-gnu/libstdc++.so.6

8 0x00007f95b7da96db in start_thread (arg=0x7f933bbfe700)

at pthread_create.c:463

9 0x00007f95b83c371f in clone ()

---Type <return> to continue, or q <return> to quit--- at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Why?

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Comments

Hello,

can you provide more details ?

Is this happening when you launch ... ? - A demo (which one) - your own world - your own plugin/code

This trace is not enough to understand what is going on.

ahcorde gravatar imageahcorde ( 2021-01-13 05:00:30 -0500 )edit

Hi,

I've only downloaded the GitHub's project

https://github.com/PierreExeter/jaco-gym

installed the several packages, and evoked

roslaunch kinova_gazebo robot_launch_render.launch kinova_robotType:=j2n6s300

and

python3 scripts/1_train_ppo2.py

. After the evoking, gzserver makes the "segmentation fault" sporadically.

I'm using Ubuntu18.04, ROS melodic, Python 3.6.9, gym-0.18.0 and gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0.

It seems to me that stack destruction is occurring.

Kazu

KASUYASU gravatar imageKASUYASU ( 2021-01-14 01:46:11 -0500 )edit

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answered 2021-01-19 04:28:51 -0500

KASUYASU gravatar image

This is NOT the true answer, but I rewrite the code of 'Event.hh' like

  public: template< typename P >
          __attribute__((optimize("O0"))) void Signal(const P &_p)
  {
std::lock_guard<std::mutex> lock(this->mutex);
    this->Cleanup();

    this->SetSignaled(true);
    for ( auto i = this->connections.begin(); i != this->connections.end(); ++i )
    {
      bool *b = nullptr;
      b = &i->second->on;
      if (b == nullptr) {
            ConnectionCount();
            b = &i->second->on;
            if (b == nullptr) {
                    std::cout << "Can't get pointer &i->second->on !!\n";
                    continue;
            }
      }
      std::function<T> (*func);
      func = &i->second->callback;
      if (*b == true)
        (*func)(_p);
    }
  }

and add the function 'ConnectionCount()' to 'Cleanup()' like

unsigned int EventT<T>::Cleanup()
{
  std::lock_guard<std::mutex> lock(this->mutex_2);
  // Remove all queue connections.
  for (auto &conn : this->connectionsToRemove) {
    this->connections.erase(conn);
    ConnectionCount();
  }
  this->connectionsToRemove.clear();
  return ConnectionCount();
}

Maybe , there exists some bugs in the std::map, however above tampering reduces the segmentation fault dramatically.

Kazu

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Comments

From the view point of source code, maybe, the developers of this project do not have the correct knowledge of thread programming, mutex, and atomic memory access. Of course, you are free to use or not use such products.

Kazu

KASUYASU gravatar imageKASUYASU ( 2021-02-03 04:49:56 -0500 )edit
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Asked: 2021-01-08 06:28:05 -0500

Seen: 110 times

Last updated: Jan 19