I got another crash, with another backtrace but triggered by similar actions. In this case I was placing a hierarchical pin in the symbol for a subsheet.

Version: (5.1.0-161-gd928aa978), debug build


(gdb) bt
#0  0x00007f53fbb8b9f2 in std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::length() const (this=0x6500000065)
    at /build/gcc/src/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.h:936
#1  0x00007f53fbb8b9f2 in std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >::_M_assign(std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> > const&)
    (this=0x7ffc651b9d88, __str=<error reading variable: Cannot access memory at address 0x650000006d>) at /build/gcc/src/gcc-build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/basic_string.tcc:259
#2  0x00007f53fcbf62e1 in wxStringTokenizer::Reinit(wxString const&) () at /usr/lib/libwx_baseu-3.0.so.0
#3  0x00007f53fcbf6891 in wxStringTokenizer::SetString(wxString const&, wxString const&, wxStringTokenizerMode) () at /usr/lib/libwx_baseu-3.0.so.0
#4  0x00007f53ed55c3c2 in SCH_COMPONENT::GetRef(SCH_SHEET_PATH const*) (this=0x55c963762ef0, sheet=0x7ffc651ba090) at /home/nickoe/kicad-source-mirror/eeschema/sch_component.cpp:593
#5  0x00007f53ed5ca6ec in SCH_PIN::GetDefaultNetName(SCH_SHEET_PATH) (this=0x55c963768060, aPath=...) at /home/nickoe/kicad-source-mirror/eeschema/sch_pin.cpp:75
#6  0x00007f53ed49fdda in CONNECTION_GRAPH::updateItemConnectivity(SCH_SHEET_PATH, std::vector<SCH_ITEM*, std::allocator<SCH_ITEM*> >) (this=0x55c9532e7a20, aSheet=..., aItemList=std::vector of length 205, capacity 205 = {...})
    at /home/nickoe/kicad-source-mirror/eeschema/connection_graph.cpp:376
#7  0x00007f53ed49f559 in CONNECTION_GRAPH::Recalculate(SCH_SHEET_LIST, bool) (this=0x55c9532e7a20, aSheetList=..., aUnconditional=true) at /home/nickoe/kicad-source-mirror/eeschema/connection_graph.cpp:316
#8  0x00007f53ed5fe93f in SCH_EDIT_FRAME::RecalculateConnections() (this=0x55c955b45110) at /home/nickoe/kicad-source-mirror/eeschema/sch_edit_frame.cpp:1537
#9  0x00007f53ed5fdd85 in SCH_EDIT_FRAME::addCurrentItemToScreen() (this=0x55c955b45110) at /home/nickoe/kicad-source-mirror/eeschema/sch_edit_frame.cpp:1462
#10 0x00007f53ed523973 in SCH_EDIT_FRAME::OnLeftClick(wxDC*, wxPoint const&) (this=0x55c955b45110, aDC=0x0, aPosition=...) at /home/nickoe/kicad-source-mirror/eeschema/onleftclick.cpp:90
#11 0x00007f53ed53c100 in SCH_DRAW_PANEL::OnMouseEvent(wxMouseEvent&) (this=0x55c9559e3a70, event=...) at /home/nickoe/kicad-source-mirror/eeschema/sch_draw_panel.cpp:363
#12 0x00007f53fcc8a89e in wxEvtHandler::ProcessEventIfMatchesId(wxEventTableEntryBase const&, wxEvtHandler*, wxEvent&) () at /usr/lib/libwx_baseu-3.0.so.0
#13 0x00007f53fcc8ac1b in wxEvtHandler::SearchDynamicEventTable(wxEvent&) () at /usr/lib/libwx_baseu-3.0.so.0
#14 0x00007f53fcc8acb1 in wxEvtHandler::TryHereOnly(wxEvent&) () at /usr/lib/libwx_baseu-3.0.so.0
#15 0x00007f53fcc8ad64 in wxEvtHandler::ProcessEventLocally(wxEvent&) () at /usr/lib/libwx_baseu-3.0.so.0
#16 0x00007f53fcc8ae02 in wxEvtHandler::ProcessEvent(wxEvent&) () at /usr/lib/libwx_baseu-3.0.so.0
#17 0x00007f53fcc8b817 in wxEvtHandler::ProcessPendingEvents() () at /usr/lib/libwx_baseu-3.0.so.0
#18 0x00007f53fcb1d9e8 in wxAppConsoleBase::ProcessPendingEvents() () at /usr/lib/libwx_baseu-3.0.so.0
#19 0x00007f53fcfedd7a in wxApp::DoIdle() () at /usr/lib/libwx_gtk3u_core-3.0.so.0
#20 0x00007f53fcfede94 in  () at /usr/lib/libwx_gtk3u_core-3.0.so.0
#21 0x00007f53fac05661 in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#22 0x00007f53fac07739 in  () at /usr/lib/libglib-2.0.so.0
#23 0x00007f53fac086d2 in g_main_loop_run () at /usr/lib/libglib-2.0.so.0
#24 0x00007f53fb20a94f in gtk_main () at /usr/lib/libgtk-3.so.0
#25 0x00007f53fd00ac46 in wxGUIEventLoop::DoRun() () at /usr/lib/libwx_gtk3u_core-3.0.so.0
#26 0x00007f53fcb57bae in wxEventLoopBase::Run() () at /usr/lib/libwx_baseu-3.0.so.0
#27 0x00007f53fcb1c517 in wxAppConsoleBase::MainLoop() () at /usr/lib/libwx_baseu-3.0.so.0
#28 0x000055c95172d43d in APP_KICAD::OnRun() (this=0x55c953265ec0) at /home/nickoe/kicad-source-mirror/kicad/kicad.cpp:267
#29 0x00007f53fcba44c8 in wxEntry(int&, wchar_t**) () at /usr/lib/libwx_baseu-3.0.so.0
#30 0x000055c95172bc47 in main(int, char**) (argc=1, argv=0x7ffc651bae18) at /home/nickoe/kicad-source-mirror/kicad/kicad.cpp:298