josh@dreamland:~/Projects/InkScape-Experimental/experimental$ gdb bin/inkscape
GNU gdb (Ubuntu 7.7-0ubuntu3.1) 7.7
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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Reading symbols from bin/inkscape...done.
(gdb) run
Starting program: /home/josh/Projects/InkScape-Experimental/experimental/bin/inkscape
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffd7d66700 (LWP 20242)]
[New Thread 0x7fffd6ceb700 (LWP 20243)]
[New Thread 0x7fffd5ebe700 (LWP 20244)]
[New Thread 0x7fffd56bd700 (LWP 20245)]
[Thread 0x7fffd5ebe700 (LWP 20244) exited]

(inkscape:20238): GLib-GObject-CRITICAL **: g_object_set: assertion 'G_IS_OBJECT (object)' failed
[Thread 0x7fffd56bd700 (LWP 20245) exited]
[Thread 0x7fffd6ceb700 (LWP 20243) exited]
[Thread 0x7fffd7d66700 (LWP 20242) exited]
[Inferior 1 (process 20238) exited normally]
(gdb) run

--
-- In this run, I failed to make the gradient editor crash it, but managed to get undo to crash
--

Starting program: /home/josh/Projects/InkScape-Experimental/experimental/bin/inkscape
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffd7d1e700 (LWP 20251)]
[New Thread 0x7fffd6ca3700 (LWP 20252)]
[New Thread 0x7fffd5e76700 (LWP 20253)]
[New Thread 0x7fffd5675700 (LWP 20254)]
[Thread 0x7fffd5e76700 (LWP 20253) exited]

** (inkscape:20250): CRITICAL **: SPGradient* chase_hrefs(SPGradient*, bool (*)(const SPGradient*)): assertion 'SP_IS_GRADIENT(src)' failed

Program received signal SIGSEGV, Segmentation fault.
SPGradient::getFirstStop (this=0x0) at sp-gradient.cpp:561
561	    for (SPObject *ochild = firstChild(); ochild && !first; ochild = ochild->getNext()) {
(gdb) bt
#0  SPGradient::getFirstStop (this=0x0) at sp-gradient.cpp:561
#1  0x00000000004c9d3d in sp_get_stop_i (gradient=<optimized out>, stop_i=0)
    at gradient-chemistry.cpp:605
#2  0x00000000004d3586 in GrDrag::selectByStop (this=0x3166bc0, stop=0x0,
    add_to_selection=false, override=true) at gradient-drag.cpp:1780
#3  0x00000000007de816 in select_drag_by_stop (ev=<optimized out>,
    gradient=<optimized out>, data=<optimized out>)
    at widgets/gradient-toolbar.cpp:636
#4  gr_stop_combo_changed (data=0x34efcd0) at widgets/gradient-toolbar.cpp:967
#5  0x00007ffff14ea5e7 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#6  0x00007ffff1503088 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#7  0x00007ffff1503ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#8  0x00000000007d50c9 in resync_active (act=0x353f160, active=0,
    override=<optimized out>) at widgets/ege-select-one-action.cpp:905
#9  0x00007ffff14f1b39 in g_object_set_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#10 0x00007ffff14f2397 in g_object_set ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#11 0x00000000007d60b5 in combo_changed_cb (widget=<optimized out>,
    user_data=<optimized out>) at widgets/ege-select-one-action.cpp:1017
---Type <return> to continue, or q <return> to quit---
#12 0x00007ffff14ea5e7 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007ffff1503088 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#14 0x00007ffff1503ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#15 0x00007ffff694ae26 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#16 0x00007ffff694d1b8 in gtk_combo_box_set_active ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#17 0x00000000007e00c0 in select_stop_by_drag (data=0x34efcd0, ev=0x3b206e0,
    gradient=<optimized out>, combo_box=0x3601c70)
    at widgets/gradient-toolbar.cpp:677
#18 gr_tb_selection_changed (data=<optimized out>)
    at widgets/gradient-toolbar.cpp:408
#19 0x000000000058ede4 in emit (_A_a2=@0x7fffffffd9cc: 2,
    _A_a1=@0x7fffffffd9d8: 0x16bdaf0, impl=0x3482b10)
    at /usr/include/sigc++-2.0/sigc++/signal.h:1252
#20 emit (this=0x16bdb80, _A_a2=@0x7fffffffd9cc: 2,
    _A_a1=@0x7fffffffd9d8: 0x16bdaf0)
    at /usr/include/sigc++-2.0/sigc++/signal.h:2891
#21 SPObject::emitModified (this=this@entry=0x16bdaf0, flags=flags@entry=0)
    at sp-object.cpp:1217
---Type <return> to continue, or q <return> to quit---
#22 0x000000000056c670 in SPGroup::modified (this=this@entry=0x2a374c0,
    flags=0, flags@entry=2) at sp-item-group.cpp:225
#23 0x000000000059aef0 in SPRoot::modified (this=0x2a374c0, flags=2)
    at sp-root.cpp:315
#24 0x000000000058ed40 in SPObject::emitModified (this=0x2a374c0,
    flags=flags@entry=0) at sp-object.cpp:1215
#25 0x00000000004ac1d8 in SPDocument::_emitModified (this=this@entry=0x1d64ea0)
    at document.cpp:903
#26 0x00000000004ac93a in SPDocument::_updateDocument (
    this=this@entry=0x1d64ea0) at document.cpp:1070
#27 0x00000000004aca39 in sp_document_idle_handler (data=0x1d64ea0)
    at document.cpp:1134
#28 0x00007ffff121ace5 in g_main_context_dispatch ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#29 0x00007ffff121b048 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#30 0x00007ffff121b30a in g_main_loop_run ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#31 0x00007ffff69ca447 in gtk_main ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#32 0x000000000047a2ac in sp_main_gui (argc=1, argv=0x7fffffffdf58)
    at main.cpp:1075
#33 0x00007ffff03efec5 in __libc_start_main (
    main=0x45bbf0 <main(int, char**)>, argc=1, argv=0x7fffffffdf58,
---Type <return> to continue, or q <return> to quit---
    init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
    stack_end=0x7fffffffdf48) at libc-start.c:287
#34 0x0000000000476a8f in _start ()
(gdb) run

--
-- Second verse: same as the first
--

The program being debugged has been started already.
Start it from the beginning? (y or n) y

Starting program: /home/josh/Projects/InkScape-Experimental/experimental/bin/inkscape
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffd7d42700 (LWP 20266)]
[New Thread 0x7fffd6cc7700 (LWP 20267)]
[New Thread 0x7fffd5e9a700 (LWP 20268)]
[New Thread 0x7fffd5699700 (LWP 20269)]
[Thread 0x7fffd5e9a700 (LWP 20268) exited]
[Thread 0x7fffd5699700 (LWP 20269) exited]

** (inkscape:20265): CRITICAL **: SPGradient* chase_hrefs(SPGradient*, bool (*)(const SPGradient*)): assertion 'SP_IS_GRADIENT(src)' failed

Program received signal SIGSEGV, Segmentation fault.
SPGradient::getFirstStop (this=0x0) at sp-gradient.cpp:561
561	    for (SPObject *ochild = firstChild(); ochild && !first; ochild = ochild->getNext()) {
(gdb) bt
#0  SPGradient::getFirstStop (this=0x0) at sp-gradient.cpp:561
#1  0x00000000004c9d3d in sp_get_stop_i (gradient=<optimized out>, stop_i=0)
    at gradient-chemistry.cpp:605
#2  0x00000000004d3586 in GrDrag::selectByStop (this=0x7347ba0, stop=0x0,
    add_to_selection=false, override=true) at gradient-drag.cpp:1780
#3  0x00000000007de816 in select_drag_by_stop (ev=<optimized out>,
    gradient=<optimized out>, data=<optimized out>)
    at widgets/gradient-toolbar.cpp:636
#4  gr_stop_combo_changed (data=0x34f7cd0) at widgets/gradient-toolbar.cpp:967
#5  0x00007ffff14ea5e7 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#6  0x00007ffff1503088 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#7  0x00007ffff1503ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#8  0x00000000007d50c9 in resync_active (act=0x3548160, active=0,
    override=<optimized out>) at widgets/ege-select-one-action.cpp:905
#9  0x00007ffff14f1b39 in g_object_set_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#10 0x00007ffff14f2397 in g_object_set ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#11 0x00000000007d60b5 in combo_changed_cb (widget=<optimized out>,
    user_data=<optimized out>) at widgets/ege-select-one-action.cpp:1017
---Type <return> to continue, or q <return> to quit---
#12 0x00007ffff14ea5e7 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007ffff1503088 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#14 0x00007ffff1503ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#15 0x00007ffff694ae26 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#16 0x00007ffff694d1b8 in gtk_combo_box_set_active ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#17 0x00000000007e00c0 in select_stop_by_drag (data=0x34f7cd0, ev=0x73394f0,
    gradient=<optimized out>, combo_box=0x360ac70)
    at widgets/gradient-toolbar.cpp:677
#18 gr_tb_selection_changed (data=<optimized out>)
    at widgets/gradient-toolbar.cpp:408
#19 0x000000000058ede4 in emit (_A_a2=@0x7fffffffd9cc: 2,
    _A_a1=@0x7fffffffd9d8: 0x2a3ee60, impl=0x348b070)
    at /usr/include/sigc++-2.0/sigc++/signal.h:1252
#20 emit (this=0x2a3eef0, _A_a2=@0x7fffffffd9cc: 2,
    _A_a1=@0x7fffffffd9d8: 0x2a3ee60)
    at /usr/include/sigc++-2.0/sigc++/signal.h:2891
#21 SPObject::emitModified (this=this@entry=0x2a3ee60, flags=flags@entry=0)
    at sp-object.cpp:1217
---Type <return> to continue, or q <return> to quit---
#22 0x000000000056c670 in SPGroup::modified (this=this@entry=0x1793960,
    flags=0, flags@entry=2) at sp-item-group.cpp:225
#23 0x000000000059aef0 in SPRoot::modified (this=0x1793960, flags=2)
    at sp-root.cpp:315
#24 0x000000000058ed40 in SPObject::emitModified (this=0x1793960,
    flags=flags@entry=0) at sp-object.cpp:1215
#25 0x00000000004ac1d8 in SPDocument::_emitModified (this=this@entry=0x1d64ea0)
    at document.cpp:903
#26 0x00000000004ac93a in SPDocument::_updateDocument (
    this=this@entry=0x1d64ea0) at document.cpp:1070
#27 0x00000000004aca39 in sp_document_idle_handler (data=0x1d64ea0)
    at document.cpp:1134
#28 0x00007ffff121ace5 in g_main_context_dispatch ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#29 0x00007ffff121b048 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#30 0x00007ffff121b30a in g_main_loop_run ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#31 0x00007ffff69ca447 in gtk_main ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#32 0x000000000047a2ac in sp_main_gui (argc=1, argv=0x7fffffffdf58)
    at main.cpp:1075
#33 0x00007ffff03efec5 in __libc_start_main (
    main=0x45bbf0 <main(int, char**)>, argc=1, argv=0x7fffffffdf58,
---Type <return> to continue, or q <return> to quit---
    init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
    stack_end=0x7fffffffdf48) at libc-start.c:287
#34 0x0000000000476a8f in _start ()
(gdb) stop
(gdb) kill
Kill the program being debugged? (y or n) y
(gdb) run

--
-- This time, I managed to get the gradient crash
--

Starting program: /home/josh/Projects/InkScape-Experimental/experimental/bin/inkscape
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffd7d89700 (LWP 20276)]
[New Thread 0x7fffd6d0e700 (LWP 20277)]
[New Thread 0x7fffd5ee1700 (LWP 20278)]
[New Thread 0x7fffd56e0700 (LWP 20279)]
[Thread 0x7fffd5ee1700 (LWP 20278) exited]
[Thread 0x7fffd56e0700 (LWP 20279) exited]

Program received signal SIGSEGV, Segmentation fault.
0x00000000004d30dd in GrDragger::deselect (this=0x403aee0)
    at gradient-drag.cpp:1711
1711	    g_object_set (G_OBJECT (this->knot->item), "fill_color", GR_KNOT_COLOR_NORMAL, NULL);
(gdb) bt
#0  0x00000000004d30dd in GrDragger::deselect (this=0x403aee0)
    at gradient-drag.cpp:1711
#1  0x00000000004d3148 in GrDrag::deselect_all (this=this@entry=0x3143760)
    at gradient-drag.cpp:1727
#2  0x00000000004d34cc in GrDrag::setSelected (this=0x3143760,
    dragger=0x7365f90, add_to_selection=<optimized out>,
    override=<optimized out>) at gradient-drag.cpp:1837
#3  0x00000000004d9c5a in gr_knot_moved_handler (knot=0x7367d60, ppointer=...,
    state=256, data=0x403aee0) at gradient-drag.cpp:793
#4  0x00000000004e7bb7 in emit (_A_a3=@0x7fffffffd08c: 256, _A_a2=...,
    _A_a1=@0x7fffffffd098: 0x7367d60, impl=0x7366be0)
    at /usr/include/sigc++-2.0/sigc++/signal.h:1501
#5  emit (this=0x7366d08, _A_a3=@0x7fffffffd08c: 256, _A_a2=...,
    _A_a1=@0x7fffffffd098: 0x7367d60)
    at /usr/include/sigc++-2.0/sigc++/signal.h:3003
#6  SPKnot::setPosition (this=this@entry=0x7367d60, p=..., state=256)
    at knot.cpp:408
#7  0x00000000004e7e32 in SPKnot::requestPosition (this=this@entry=0x7367d60,
    p=..., state=256) at knot.cpp:397
#8  0x00000000004e7f0f in sp_knot_handler_request_position (event=0x401c0e0,
    knot=0x7367d60) at knot.cpp:375
#9  0x00000000004e8afc in sp_knot_handler (event=0x401c0e0, knot=0x7367d60)
    at knot.cpp:299
---Type <return> to continue, or q <return> to quit---
#10 0x00000000006ef72d in sp_marshal_BOOLEAN__POINTER (closure=0x7364030,
    return_value=0x7fffffffd4b0, n_param_values=<optimized out>,
    param_values=0x7fffffffd3e0, invocation_hint=<optimized out>,
    marshal_data=0x0) at helper/sp-marshal.cpp:124
#11 0x00007ffff14ea3b8 in g_closure_invoke ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#12 0x00007ffff14fbd3d in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007ffff15036f9 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#14 0x00007ffff1503ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#15 0x0000000000635f69 in SPCanvasImpl::emitEvent (canvas=<optimized out>,
    event=0x4026b10) at display/sp-canvas.cpp:1515
#16 0x0000000000636346 in SPCanvasImpl::handleMotion (widget=0x306e000,
    event=0x4026b10) at display/sp-canvas.cpp:1758
#17 0x00007ffff69cc815 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#18 0x00007ffff14ea3b8 in g_closure_invoke ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#19 0x00007ffff14fbafb in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#20 0x00007ffff15036f9 in g_signal_emit_valist ()
---Type <return> to continue, or q <return> to quit---
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#21 0x00007ffff1503ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#22 0x00007ffff6adc724 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#23 0x00007ffff69cafc4 in gtk_propagate_event ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#24 0x00007ffff69cb37b in gtk_main_do_event ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#25 0x00007ffff66461ec in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0
#26 0x00007ffff121ae04 in g_main_context_dispatch ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#27 0x00007ffff121b048 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#28 0x00007ffff121b30a in g_main_loop_run ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#29 0x00007ffff69ca447 in gtk_main ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#30 0x000000000047a2ac in sp_main_gui (argc=1, argv=0x7fffffffdf58)
    at main.cpp:1075
#31 0x00007ffff03efec5 in __libc_start_main (
    main=0x45bbf0 <main(int, char**)>, argc=1, argv=0x7fffffffdf58,
    init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
---Type <return> to continue, or q <return> to quit---
    stack_end=0x7fffffffdf48) at libc-start.c:287
#32 0x0000000000476a8f in _start ()