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I was trying to capture exactly which method, or at least which class crashed my code from
messages returned by backtrace after received the SIGSEGV signal. Is it because the crashed method was executing on another thread, therefore backtrace was unable to do so (see the first line of my log - process id is 7fdae0268700, i added code there to crash my app)? Any recommendation to this issue please?

    2013-03-07 17:43:42.863709502 [7fdae0268700] DEBUG data_service - I Crash You! Location
    2013-03-07 17:43:42.863804548 [7fdae7d1c720] INFO  service_runner - Receive signal 11
    2013-03-07 17:43:42.870357301 [7fdae7d1c720] DEBUG service_runner - [bt]: (0) ../Debug/MyAppService : my_app_service_lib::service_runner::handle_crash_stop(boost::system::error_code const&, int)+0x7e [0xcccf54]
    2013-03-07 17:43:42.870369392 [7fdae7d1c720] DEBUG service_runner - [bt]: (1) ../Debug/MyAppService : boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>::operator()(my_app_service_lib::service_runner*, boost::system::error_code const&, int) const+0x74 [0xcd8278]
    2013-03-07 17:43:42.870384611 [7fdae7d1c720] DEBUG service_runner - [bt]: (2) ../Debug/MyAppService : void boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> >::operator()<boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list2<boost::system::error_code const&, int const&> >(boost::_bi::type<void>, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>&, boost::_bi::list2<boost::system::error_code const&, int const&>&, int)+0x7c [0xcd80c6]
    2013-03-07 17:43:42.870395158 [7fdae7d1c720] DEBUG service_runner - [bt]: (3) ../Debug/MyAppService : void boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > >::operator()<boost::system::error_code, int>(boost::system::error_code const&, int const&)+0x4c [0xcd7f0e]
    2013-03-07 17:43:42.870405480 [7fdae7d1c720] DEBUG service_runner - [bt]: (4) ../Debug/MyAppService : boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > >, boost::system::error_code, int>::operator()()+0x2b [0xcd7e15]
    2013-03-07 17:43:42.870419010 [7fdae7d1c720] DEBUG service_runner - [bt]: (5) ../Debug/MyAppService : void boost::asio::asio_handler_invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > >, boost::system::error_code, int> >(boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > >, boost::system::error_code, int>, ...)+0x62 [0xcd7d2e]
    2013-03-07 17:43:42.870436180 [7fdae7d1c720] DEBUG service_runner - [bt]: (6) ../Debug/MyAppService : void boost_asio_handler_invoke_helpers::invoke<boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > >, boost::system::error_code, int>, boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > > >(boost::asio::detail::binder2<boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > >, boost::system::error_code, int>&, boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > >&)+0x64 [0xcd7bea]
    2013-03-07 17:43:42.870447863 [7fdae7d1c720] DEBUG service_runner - [bt]: (7) ../Debug/MyAppService : boost::asio::detail::signal_handler<boost::_bi::bind_t<void, boost::_mfi::mf2<void, my_app_service_lib::service_runner, boost::system::error_code const&, int>, boost::_bi::list3<boost::_bi::value<my_app_service_lib::service_runner*>, boost::arg<1>, boost::arg<2> > > >::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned long)+0xb9 [0xcd78db]
    2013-03-07 17:43:42.870454915 [7fdae7d1c720] DEBUG service_runner - [bt]: (8) ../Debug/MyAppService : boost::asio::detail::task_io_service_operation::complete(boost::asio::detail::task_io_service&, boost::system::error_code const&, unsigned long)+0x32 [0xcce3ba]
    2013-03-07 17:43:42.870462704 [7fdae7d1c720] DEBUG service_runner - [bt]: (9) ../Debug/MyAppService : boost::asio::detail::task_io_service::do_run_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&, boost::asio::detail::task_io_service::thread_info&, boost::system::error_code const&)+0x1a1 [0xcd09b3]
    2013-03-07 17:43:42.870469226 [7fdae7d1c720] DEBUG service_runner - [bt]: (10) ../Debug/MyAppService : boost::asio::detail::task_io_service::run(boost::system::error_code&)+0x137 [0xcd050b]
    2013-03-07 17:43:42.870474974 [7fdae7d1c720] DEBUG service_runner - [bt]: (11) ../Debug/MyAppService : boost::asio::io_service::run()+0x2f [0xcd0d31]
    2013-03-07 17:43:42.870480654 [7fdae7d1c720] DEBUG service_runner - [bt]: (12) ../Debug/MyAppService : my_app_service_lib::service_runner::run()+0x97 [0xcccda9]
    2013-03-07 17:43:42.870486438 [7fdae7d1c720] DEBUG service_runner - [bt]: (13) ../Debug/MyAppService : main+0x4cc [0xcc5838]
    2013-03-07 17:43:42.870491274 [7fdae7d1c720] DEBUG service_runner - [bt]: (14) /lib64/libc.so.6 : __libc_start_main+0xfd [0x3f0f01ecdd]
    2013-03-07 17:43:42.870495884 [7fdae7d1c720] DEBUG service_runner - [bt]: (15) ../Debug/MyAppService() [0xcc5289]
Bryan Fok
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    Can you not just get a core dump, and examine that? This will give your the state of your entire program, including all threads, variables etc. – NPE Mar 07 '13 at 10:07
  • Tough for most to debug without at least a very small reproducer to share. – Eric Johnson Mar 07 '13 at 10:08
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    The backtrace always refers to the thread where `backtrace` and `backtrace_symbols` was called from. Other than that, I don't exactly understand what you are asking/expecting... – Daniel Frey Mar 07 '13 at 10:08
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    Most likely, `my_app_service_lib::service_runner` doesn't outlive the completion handler. Consider using `shared_from_this` idiom. – Igor R. Mar 07 '13 at 10:30

1 Answers1

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If you're using a handler invoked by boost::asio::signal_set::async_wait to call backtrace_symbols(3) this won't work. The signal_set class uses a signalfd on Linux, other platforms may use the pipe-select-interrupt trick, I dontt know specifically. So when your handler is invoked it won't be from the thread that caused the SEGV.

It's generally not adviseable to try and do anything smart/cute upon encountering a SEGV signal. You cannot reliably continue execution. I suggest not handling the SEGV signal and instead configure your system to core dump when a process has terminated abnormally, then analyze the core dump.

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Sam Miller
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  • Thank you very much for your clarify, and advance Sam. I tried out the core dump solution as @NPE advance at yesterday, and it works well. And in my opinion, catching SEGV signal within the program has it own advantages which core dump could not provide. – Bryan Fok Mar 08 '13 at 01:44