<div dir="ltr"><div dir="ltr">Hey Héctor,</div><div class="gmail_quote"><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg-6874048365838888947"><div lang="ES" style="overflow-wrap: break-word;"><div class="m_-6964447716312237692WordSection1"> 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: MMModemPtr ModemManagerFacade::getModemPtr(const std::string &imei) { MMObject *object = getObject(imei); if (object == nullptr) { return MMModemPtr(nullptr, &g_object_unref); } return MMModemPtr(mm_object_get_modem(object), &g_object_unref); } It returns a MMModemPtr type, which is a unique pointer: using MMModemPtr = std::unique_ptr<MMModem, decltype(&g_object_unref)>;///< MMModem Unique pointer with custom deleter and it’s checked every time that function is called as in: MMModemPtr modem = getModemPtr(imei); if (modem == nullptr) { return DPY_UNAVAILABLE; } MMobject is stored in a map std::map<std::string, MMObject*> mImeiToObjectMap; and obtained in MMObject* ModemManagerFacade::getObject(std::string imei) { /* Some previous checkings … …and*/ auto it = mImeiToObjectMap.find(imei); if (it == mImeiToObjectMap.end()) { return nullptr; } return (it->second); } But I don’t think MMobject pointer is the problem as it’s checked inside mm_object_get_modem function: MMModem * mm_object_get_modem (MMObject *self) { MMModem *modem; g_return_val_if_fail (MM_IS_OBJECT (MM_GDBUS_OBJECT (self)), NULL); modem = (MMModem *)mm_gdbus_object_get_modem (MM_GDBUS_OBJECT (self)); g_warn_if_fail (MM_IS_MODEM (modem)); return modem; } and the backtrace shows that the program terminates after calling mm_gdbus_object_get_modem Program terminated with signal SIGSEGV, Segmentation fault. #0 0x0000ffffad048ab8 in g_hash_table_lookup () from /usr/lib/libglib-2.0.so.0 [Current thread is 1 (LWP 10802)] (gdb) bt #0 0x0000ffffad048ab8 in g_hash_table_lookup () from /usr/lib/libglib-2.0.so.0 #1 0x0000ffffad2f5824 in ?? () from /usr/lib/libgio-2.0.so.0 </div></div></div></blockquote><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg-6874048365838888947"><div lang="ES" style="overflow-wrap: break-word;"><div class="m_-6964447716312237692WordSection1"> #2 0x0000ffffad4629dc in mm_gdbus_object_get_modem () from /usr/lib/libmm-glib.so.0 #3 0x0000ffffad422e2c in mm_object_get_modem () from /usr/lib/libmm-glib.so.0 #4 0x0000aaaabff73124 in ModemManagerFacade::getModemPtr(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) () #5 0x0000aaaabff745f0 in ModemManagerFacade::getDominantTechnologySignalQuality(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, dpyModem::SignalQuality&, bool&) () #6 0x0000aaaabff5d97c in ModemManagerDevice::update_signalQuality() () #7 0x0000aaaabffbb050 in ModemSupervisor::updateModemParameters() () #8 0x0000aaaabffbbc44 in ModemSupervisor::checkModemStatus(boost::system::error_code const&, dpyModem::ModemState) () #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) () #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&) () #11 0x0000aaaabffe704c in ModemService::operator()(boost::application::basic_context&) () #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&) () #13 0x0000aaaabfedc9a0 in main () Any ideas about why this can be happening? Has it ever been seen before?</div></div></div></blockquote><div> </div><div> </div><div><div>i'd bet this is some memory corruption happening somewhere. Is the issue easily reproducible? maybe you can prepare a small reproducer program that triggers this issue for us to analyze? Otherwise, I suggest you try to run under valgrind to see if you get any memory related issues reported there.</div><div> </div><div>The only thing I can say about this issue is that I don't recall anything similar to this reported lately in the past years. libmm-glib is used by multiple other projects, so there's a high chance that the issue is indeed a memory corruption somewhere in your project. Maybe a double free, or a use-after-free, or something like that.</div><div> </div><div>Also please note that the g_return_if_fail() calls may be disabled in the build! you should ensure these are being used in your build before assuming they're being called.</div><div> </div><div>Sorry I cannot help more :/</div></div><div> </div></div>-- <div dir="ltr" class="gmail_signature"><div dir="ltr"><div>Aleksander</div></div></div></div>