<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta name="Generator" content="Microsoft Word 15 (filtered medium)"> <style></style> </head> <body lang="ES" link="#0563C1" vlink="#954F72" style="word-wrap:break-word"> <div class="WordSection1"> Hi.<o:p></o:p> <o:p> </o:p> We are using ModemManager 1.18.8 library and sometimes we got segmentation fault when calling mm_object_get_modem function. It happens from time to time, no clues about circumstances, as our code is continuously inquiring for modem object in this function:<o:p></o:p> <o:p> </o:p> MMModemPtr ModemManagerFacade::getModemPtr(const std::string &imei)<o:p></o:p> {<o:p></o:p> MMObject *object = getObject(imei);<o:p></o:p> if (object == nullptr) {<o:p></o:p> return MMModemPtr(nullptr, &g_object_unref);<o:p></o:p> }<o:p></o:p> <o:p> </o:p> return MMModemPtr(mm_object_get_modem(object), &g_object_unref);<o:p></o:p> }<o:p></o:p> <o:p> </o:p> It returns a MMModemPtr type, which is a unique pointer:<o:p></o:p> using MMModemPtr = std::unique_ptr<MMModem, decltype(&g_object_unref)>;///< MMModem Unique pointer with custom deleter<o:p></o:p> <o:p> </o:p> and it’s checked every time that function is called as in:<o:p></o:p> MMModemPtr modem = getModemPtr(imei);<o:p></o:p> if (modem == nullptr) {<o:p></o:p> return DPY_UNAVAILABLE;<o:p></o:p> }<o:p></o:p> <o:p> </o:p> MMobject is stored in a map<o:p></o:p> std::map<std::string, MMObject*> mImeiToObjectMap;<o:p></o:p> <o:p> </o:p> and obtained in <o:p></o:p> MMObject* ModemManagerFacade::getObject(std::string imei)<o:p></o:p> {<o:p></o:p> /* Some previous checkings …<o:p></o:p> …and*/<o:p></o:p> auto it = mImeiToObjectMap.find(imei);<o:p></o:p> if (it == mImeiToObjectMap.end()) {<o:p></o:p> return nullptr;<o:p></o:p> }<o:p></o:p> return (it->second);<o:p></o:p> }<o:p></o:p> <o:p> </o:p> But I don’t think MMobject pointer is the problem as it’s checked inside mm_object_get_modem function:<o:p></o:p> MMModem *<o:p></o:p> mm_object_get_modem (MMObject *self)<o:p></o:p> {<o:p></o:p> MMModem *modem;<o:p></o:p> <o:p> </o:p> g_return_val_if_fail (MM_IS_OBJECT (MM_GDBUS_OBJECT (self)), NULL);<o:p></o:p> <o:p> </o:p> modem = (MMModem *)mm_gdbus_object_get_modem (MM_GDBUS_OBJECT (self));<o:p></o:p> g_warn_if_fail (MM_IS_MODEM (modem));<o:p></o:p> return modem;<o:p></o:p> }<o:p></o:p> <o:p> </o:p> and the backtrace shows that the program terminates after calling mm_gdbus_object_get_modem<o:p></o:p> <o:p> </o:p> Program terminated with signal SIGSEGV, Segmentation fault.<o:p></o:p> #0 0x0000ffffad048ab8 in g_hash_table_lookup () from /usr/lib/libglib-2.0.so.0<o:p></o:p> [Current thread is 1 (LWP 10802)]<o:p></o:p> (gdb) bt<o:p></o:p> #0 0x0000ffffad048ab8 in g_hash_table_lookup () from /usr/lib/libglib-2.0.so.0<o:p></o:p> #1 0x0000ffffad2f5824 in ?? () from /usr/lib/libgio-2.0.so.0<o:p></o:p> #2 0x0000ffffad4629dc in mm_gdbus_object_get_modem () from /usr/lib/libmm-glib.so.0<o:p></o:p> #3 0x0000ffffad422e2c in mm_object_get_modem () from /usr/lib/libmm-glib.so.0<o:p></o:p> #4 0x0000aaaabff73124 in ModemManagerFacade::getModemPtr(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()<o:p></o:p> #5 0x0000aaaabff745f0 in ModemManagerFacade::getDominantTechnologySignalQuality(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, dpyModem::SignalQuality&, bool&) ()<o:p></o:p> #6 0x0000aaaabff5d97c in ModemManagerDevice::update_signalQuality() ()<o:p></o:p> #7 0x0000aaaabffbb050 in ModemSupervisor::updateModemParameters() ()<o:p></o:p> #8 0x0000aaaabffbbc44 in ModemSupervisor::checkModemStatus(boost::system::error_code const&, dpyModem::ModemState) ()<o:p></o:p> #9 0x0000aaaabffbcfe8 in boost::asio::detail::wait_handler<boost::_bi::bind_t<void, boost::_mfi::mf2<void, ModemSupervisor, boost::system::error_code const&, dpyModem::ModemState>, boost::_bi::list3<boost::_bi::value<ModemSupervisor*>, boost::arg<1> (*)(), boost::_bi::value<dpyModem::ModemState> > > >::do_complete(void*, boost::asio::detail::scheduler_operation*, boost::system::error_code const&, unsigned long) ()<o:p></o:p> #10 0x0000aaaabff0de38 in boost::asio::detail::scheduler::do_run_one(boost::asio::detail::conditionally_enabled_mutex::scoped_lock&, boost::asio::detail::scheduler_thread_info&, boost::system::error_code const&) ()<o:p></o:p> #11 0x0000aaaabffe704c in ModemService::operator()(boost::application::basic_context&) ()<o:p></o:p> #12 0x0000aaaabffd019c in int boost::application::launch<boost::application::common, boost::application::auto_handler<ModemService>, boost::application::basic_context>(boost::application::auto_handler<ModemService>&, boost::application::basic_context&, boost::system::error_code&) ()<o:p></o:p> #13 0x0000aaaabfedc9a0 in main ()<o:p></o:p> <o:p> </o:p> Any ideas about why this can be happening? Has it ever been seen before?<o:p></o:p> <o:p> </o:p> Thank you!<o:p></o:p> <o:p> </o:p> <table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0" width="450" style="width:337.5pt"> <tbody> <tr> <td width="150" valign="top" style="width:112.5pt;border:none;border-right:solid #DF0024 1.5pt;padding:0cm 11.25pt 0cm 0cm"> <a href="https://www.gmv.com/" target="_blank"><img border="0" width="175" height="68" style="width:1.8263in;height:.7083in" id="Imagen_x0020_1" src="cid:image001.jpg@01D99F89.0F4ED1E0" alt="Logo"></a><o:p></o:p> </td> <td valign="top" style="padding:0cm 0cm 0cm 11.25pt"> H�ctor Jim�nez M�ndez Firmware engineer T. 983 54 65 54 M. 696 297 286 Juan de Herrera, n� 17, P.T.B. 47151 Boecillo, Valladolid | Spain<o:p></o:p> </td> </tr> <tr> <td style="border:none;border-right:solid #DF0024 1.5pt;padding:0cm 0cm 0cm 0cm"> <div align="center"> <table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0" width="150" style="width:112.5pt"> <tbody> <tr> <td style="padding:0cm 0cm 0cm 0cm"> <a href="http://www.gmv.com/communication/blog" target="_blank"><img border="0" width="34" height="23" style="width:.3541in;height:.243in" id="Imagen_x0020_2" src="cid:image002.jpg@01D99F89.0F4ED1E0"></a><o:p></o:p> </td> <td width="24" style="width:18.0pt;padding:0cm 0cm 0cm 0cm"> <a href="http://www.facebook.com/infoGMV" target="_blank"><img border="0" width="22" height="22" style="width:.2291in;height:.2291in" id="Imagen_x0020_3" src="cid:image003.jpg@01D99F89.0F4ED1E0"></a><o:p></o:p> </td> <td width="24" style="width:18.0pt;padding:0cm 0cm 0cm 0cm"> <a href="http://www.twitter.com/infoGMV" target="_blank"><img border="0" width="22" height="22" style="width:.2291in;height:.2291in" id="Imagen_x0020_4" src="cid:image004.jpg@01D99F89.0F4ED1E0"></a><o:p></o:p> </td> <td width="24" style="width:18.0pt;padding:0cm 0cm 0cm 0cm"> <a href="http://www.youtube.com/infoGMV" target="_blank"><img border="0" width="22" height="22" style="width:.2291in;height:.2291in" id="Imagen_x0020_5" src="cid:image005.jpg@01D99F89.0F4ED1E0"></a><o:p></o:p> </td> <td width="24" style="width:18.0pt;padding:0cm 0cm 0cm 0cm"> <a href="https://www.instagram.com/companygmv/" target="_blank"><img border="0" width="22" height="22" style="width:.2291in;height:.2291in" id="Imagen_x0020_6" src="cid:image006.jpg@01D99F89.0F4ED1E0"></a><o:p></o:p> </td> <td width="24" style="width:18.0pt;padding:0cm 0cm 0cm 0cm"> <a href="https://www.linkedin.com/company/gmv" target="_blank"><img border="0" width="22" height="22" style="width:.2291in;height:.2291in" id="Imagen_x0020_7" src="cid:image007.jpg@01D99F89.0F4ED1E0"></a><o:p></o:p> </td> </tr> </tbody> </table> </div> </td> <td style="padding:0cm 0cm 0cm 11.25pt"> <a href="http://www.gmv.com/" target="_blank">www.gmv.com</a><o:p></o:p> </td> </tr> </tbody> </table> <o:p> </o:p> <o:p> </o:p> </div> </body> </html>