Comment 3 for bug 1458033

I can reproduce this in 0.63-4 (built from Ubuntu source) on Xubuntu 14.04 if I start a serial session, set "Local echo" to "Force on", and press some keys.

Setting a breakpoint on g_log I get this backtrace:

#0 0x00007ffff683fcf0 in g_log () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1 0x00007ffff6837c5c in g_source_remove ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2 0x0000000000467a75 in timer_change_notify (next=2367632)
    at unix/gtkwin.c:1431
#3 0x0000000000458899 in schedule_timer (ticks=ticks@entry=20,
    fn=fn@entry=0x44fe30 <term_timer>, ctx=ctx@entry=0xa15200) at timing.c:145
#4 0x000000000044d1f0 in term_schedule_update (term=term@entry=0xa15200)
    at terminal.c:1101
#5 0x000000000045819e in term_schedule_update (term=0xa15200)
    at terminal.c:1099
#6 seen_disp_event (term=0xa15200) at terminal.c:1112
#7 term_reset_cblink (term=0xa15200) at terminal.c:1151
#8 term_data (term=0xa15200, is_stderr=is_stderr@entry=0,
    data=data@entry=0xa5d8b0 "aw<\366\377\177", len=len@entry=1)
    at terminal.c:6136
#9 0x000000000046729c in from_backend (frontend=<optimised out>,
    is_stderr=is_stderr@entry=0, data=data@entry=0xa5d8b0 "aw<\366\377\177",
    len=len@entry=1) at unix/gtkwin.c:210
#10 0x0000000000415801 in c_write (ldisc=0x90f9a0, len=<optimised out>,
    buf=0xa5d8b0 "aw<\366\377\177") at ldisc.c:26
#11 ldisc_send (handle=handle@entry=0x90f9a0,
    buf=buf@entry=0xa5d8b0 "aw<\366\377\177", len=<optimised out>,
    interactive=interactive@entry=1) at ldisc.c:314
#12 0x0000000000415bac in luni_send (handle=handle@entry=0x90f9a0,
    widebuf=widebuf@entry=0xab1a10 L"a翿\xa5d8a0", len=1,
    interactive=interactive@entry=1) at ldiscucs.c:96
#13 0x0000000000415c23 in lpage_send (handle=handle@entry=0x90f9a0,
    codepage=codepage@entry=55, buf=buf@entry=0x966e40 "a", len=1,
    interactive=interactive@entry=1) at ldiscucs.c:32
#14 0x0000000000466df6 in input_method_commit_event (imc=<optimised out>,
    str=0x966e40 "a", data=0x6d86b0) at unix/gtkwin.c:1227
#15 0x00007ffff6b0af29 in g_cclosure_marshal_VOID__STRINGv ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#16 0x00007ffff6b085e7 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#17 0x00007ffff6b21088 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#18 0x00007ffff6b22212 in g_signal_emit_by_name ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#19 0x00007ffff6b0af29 in g_cclosure_marshal_VOID__STRINGv ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#20 0x00007ffff6b085e7 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#21 0x00007ffff6b21088 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#22 0x00007ffff6b21ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#23 0x00007ffff6b0af29 in g_cclosure_marshal_VOID__STRINGv ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#24 0x00007ffff6b085e7 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#25 0x00007ffff6b21088 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#26 0x00007ffff6b22212 in g_signal_emit_by_name ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#27 0x00007ffff757dd30 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#28 0x00007ffff757e52f in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#29 0x00007ffff7580293 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#30 0x00000000004689b3 in key_event (widget=<optimised out>, event=0xa60800,
    data=0x6d86b0) at unix/gtkwin.c:755
#31 0x00007ffff7596815 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#32 0x00007ffff6b083b8 in g_closure_invoke ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#33 0x00007ffff6b19d3d in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#34 0x00007ffff6b216f9 in g_signal_emit_valist ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#35 0x00007ffff6b21ce2 in g_signal_emit ()
   from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#36 0x00007ffff76a6684 in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#37 0x00007ffff7595097 in gtk_propagate_event ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#38 0x00007ffff759537b in gtk_main_do_event ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#39 0x00007ffff72101ec in ?? ()
   from /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0
#40 0x00007ffff6838e04 in g_main_context_dispatch ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#41 0x00007ffff6839048 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#42 0x00007ffff683930a in g_main_loop_run ()
   from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#43 0x00007ffff7594447 in gtk_main ()
   from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#44 0x000000000046db73 in pt_main (argc=argc@entry=1,
    argv=argv@entry=0x7fffffffda78) at unix/gtkwin.c:3889
#45 0x0000000000409de0 in main (argc=1, argv=0x7fffffffda78)
    at unix/uxputty.c:140

This was fixed upstream in
http://tartarus.org/~simon-git/gitweb/?p=putty.git;a=commit;h=e4c4bd20920e11458ab0ec0cd17c69b8bf7f6d00
(between 0.63 and 0.64). I've confirmed that that commit makes the symptom go away in my test.

If anyone thinks of backporting this fix, note that there were apparently knock-on effects:
http://tartarus.org/~simon-git/gitweb/?p=putty.git;a=commit;h=4647eded7cdc590d80327291ebe7996049de3850
and possibly
http://tartarus.org/~simon-git/gitweb/?p=putty.git;a=commit;h=bc8de8a331a035deb8623911ba01c6ec800c1dc5

(Note that there are other unrelated causes of the "Source ID 5015 was not found when attempting to remove it" warning. For instance, I encountered it when manipulating the tree-view in PuTTY's configuration dialog. I get the impression that this is a Gtk bug; I see the warning from lots of other applications too.)