clreleasecontex cause segment fault

I have a simple class which has the member cl::device, cl::context, cl::command_queue. This class is implemented as a singleton. When program finish, its destructor is called. At this time, it causes  segment fault. I find this crash produced by clreleasecontext. Example code likes as follows and I test in Mali-G76

class CLSingleton

{

static CLSingleton & get()

{

}

~CLSingleton() = default;

private:

CLSingleton();

cl::Device _device;

cl::Context _context;

cl::CommandQueue _command_queue;

}

int main()

{

CLSingleton().get();

return 0;

}