This bug is in Atlas, but since you're the maintainer I figure this is a good place to put it.
There's a segfault when using an instance of the Packed codec to marshal a string into Atlas objects. The bt is below.
You can easily test this with the latest Ember from git. Just log in as admin, bring up the Type manager, select a type, switch the codec to "packed" and then click "Send to server".
Thread [1] (Suspended: Signal 'SIGSEGV' received. Description: Segmentation fault.)
20 Atlas::Message::DecoderBase::mapEnd() /home/erik/code/worldforge/forge/libs/Atlas-C++/Atlas/Message/DecoderBase.cpp:95 0x00007f3fb7267ce5
19 Atlas::Codecs::Packed::poll() /home/erik/code/worldforge/forge/libs/Atlas-C++/Atlas/Codecs/Packed.cpp:42 0x00007f3fb7479bab
18 tolua_Atlas_Atlas_Codec_poll00() /home/erik/code/worldforge-git/ember/src/framework/bindings/lua/atlas/lua_Atlas.cpp:3792 0x00000000005448f8
17 luaD_precall() /usr/src/debug/lua-5.1.4/src/ldo.c:319 0x00007f3fb8915856
16 luaV_execute() /usr/src/debug/lua-5.1.4/src/lvm.c:587 0x00007f3fb89208e1
15 luaD_call() /usr/src/debug/lua-5.1.4/src/ldo.c:377 0x00007f3fb8915dc5
14 luaD_rawrunprotected() /usr/src/debug/lua-5.1.4/src/ldo.c:116 0x00007f3fb8915447
13 luaD_pcall() /usr/src/debug/lua-5.1.4/src/ldo.c:463 0x00007f3fb89154c5
12 lua_pcall() /usr/src/debug/lua-5.1.4/src/lapi.c:821 0x00007f3fb8910d14
11 CEGUI::LuaFunctor::operator() /home/erik/code/CEGUI-0.6.2b/ScriptingModules/CEGUILua/LuaScriptModule/src/CEGUILuaFunctor.cpp:185 0x00007f3fbc0cf61f
10 CEGUI::Event::operator() /home/erik/code/CEGUI-0.6.2b/include/CEGUISubscriberSlot.h:82 0x00007f3fb97444fa
9 CEGUI::PushButton::onMouseButtonUp() /home/erik/code/CEGUI-0.6.2b/src/elements/CEGUIPushButton.cpp:87 0x00007f3fb980471e
8 CEGUI::System::injectMouseButtonUp() /home/erik/code/CEGUI-0.6.2b/src/CEGUISystem.cpp:867 0x00007f3fb9787c81
7 EmberOgre::GUICEGUIAdapter::injectMouseButtonUp() /home/erik/code/worldforge-git/ember/src/components/ogre/GUICEGUIAdapter.cpp:215 0x000000000073c91d
6 Ember::Input::pollMouse() /home/erik/code/worldforge-git/ember/src/services/input/Input.cpp:263 0x000000000088be19
5 Ember::Input::processInput() /home/erik/code/worldforge-git/ember/src/services/input/Input.cpp:202 0x000000000088c33c
4 Ember::Application::mainLoopStep() /home/erik/code/worldforge-git/ember/src/main/Application.cpp:147 0x00000000004807b6
3 Ember::Application::mainLoop() /home/erik/code/worldforge-git/ember/src/main/Application.cpp:178 0x0000000000480fec
2 Ember::Application::start() /home/erik/code/worldforge-git/ember/src/main/Application.cpp:326 0x000000000048103a
1 main() /home/erik/code/worldforge-git/ember/src/main/Ember.cpp:215 0x000000000048921b
