This is not something that a player can reproduce I think, I'm not 100% sure but I think it crashed because I /reload npc with a shop window opened, I'm posting the dump anyway because crashes are never good and it would be good if all errors some day are handled nicely showing errors in console or something instead of crashing the server like this.
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff5e6e700 (LWP 6765)]
0x0000000000843e88 in std::less<Player*>::operator()(Player* const&, Player* const&) const ()
#0 0x0000000000843e88 in std::less<Player*>::operator()(Player* const&, Player* const&) const ()
#1 0x000000000084410c in std::_Rb_tree<Player*, Player*, std::_Identity<Player*>, std::less<Player*>, std::allocator<Player*> >::equal_range(Player* const&) ()
#2 0x0000000000843311 in std::_Rb_tree<Player*, Player*, std::_Identity<Player*>, std::less<Player*>, std::allocator<Player*> >::erase(Player* const&) ()
#3 0x0000000000842a15 in std::set<Player*, std::less<Player*>, std::allocator<Player*> >::erase(Player* const&) ()
#4 0x000000000083e562 in Npc::removeShopPlayer(Player*) ()
#5 0x000000000083de83 in Npc::onPlayerEndTrade(Player*, int, int) ()
#6 0x0000000000861680 in Player::closeShopWindow(bool) ()
#7 0x000000000083e5c4 in Npc::closeAllShopWindows() ()
#8 0x000000000083c4e8 in Npcs::reload() ()
#9 0x00000000006f0587 in Commands::reloadInfo(Player*, std::string const&, std::string const&) ()
#10 0x00000000006eec55 in Commands::exeCommand(Player*, std::string const&) ()
#11 0x0000000000755aee in Game::playerSayCommand(Player*, SpeakClasses, std::string const&) ()
#12 0x0000000000755837 in Game::playerSay(unsigned int, unsigned short, SpeakClasses, std::string const&, std::string const&) ()
#13 0x00000000008a4e60 in boost::_mfi::mf5<bool, Game, unsigned int, unsigned short, SpeakClasses, std::string const&, std::string const&>::operator()(Game*, unsigned int, unsigned short, SpeakClasses, std::string const&, std::string const&) const ()
#14 0x00000000008a1b95 in bool boost::_bi::list6<boost::_bi::value<Game*>, boost::_bi::value<unsigned int>, boost::_bi::value<unsigned short>, boost::_bi::value<SpeakClasses>, boost::_bi::value<std::string>, boost::_bi::value<std::string> >::operator()<bool, boost::_mfi::mf5<bool, Game, unsigned int, unsigned short, SpeakClasses, std::string const&, std::string const&>, boost::_bi::list0>(boost::_bi::type<bool>, boost::_mfi::mf5<bool, Game, unsigned int, unsigned short, SpeakClasses, std::string const&, std::string const&>&, boost::_bi::list0&, long) ()
#15 0x000000000089ecb9 in boost::_bi::bind_t<bool, boost::_mfi::mf5<bool, Game, unsigned int, unsigned short, SpeakClasses, std::string const&, std::string const&>, boost::_bi::list6<boost::_bi::value<Game*>, boost::_bi::value<unsigned int>, boost::_bi::value<unsigned short>, boost::_bi::value<SpeakClasses>, boost::_bi::value<std::string>, boost::_bi::value<std::string> > >::operator()() ()
#16 0x000000000089c583 in boost::detail::function::void_function_obj_invoker0<boost::_bi::bind_t<bool, boost::_mfi::mf5<bool, Game, unsigned int, unsigned short, SpeakClasses, std::string const&, std::string const&>, boost::_bi::list6<boost::_bi::value<Game*>, boost::_bi::value<unsigned int>, boost::_bi::value<unsigned short>, boost::_bi::value<SpeakClasses>, boost::_bi::value<std::string>, boost::_bi::value<std::string> > >, void>::invoke(boost::detail::function::function_buffer&) ()
#17 0x00000000008d5160 in boost::function0<void>::operator()() const ()
#18 0x00000000008d500a in Task::operator()() ()
#19 0x00000000008d4a05 in Dispatcher::dispatcherThread(void*) ()
#20 0x00000000008b503d in void boost::_bi::list1<boost::_bi::value<void*> >::operator()<void (*)(void*), boost::_bi::list0>(boost::_bi::type<void>, void (*&)(void*), boost::_bi::list0&, int) ()
#21 0x00000000008b4fe5 in boost::_bi::bind_t<void, void (*)(void*), boost::_bi::list1<boost::_bi::value<void*> > >::operator()() ()
#22 0x00000000008b4faa in boost::detail::thread_data<boost::_bi::bind_t<void, void (*)(void*), boost::_bi::list1<boost::_bi::value<void*> > > >::run() ()
#23 0x00007ffff7e79629 in ?? () from /usr/lib/libboost_thread.so.1.49.0
#24 0x00007ffff7453b50 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#25 0x00007ffff678fa7d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#26 0x0000000000000000 in ?? ()