Here's my reproduction of this bug. I do not get any output from xbacktrace (i did source src/.gdbinit) In GNU Emacs 24.5.3 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8) of 2016-06-16 on ula034034-w1 Windowing system distributor `The X.Org Foundation', version 11.0.11501000 System Description: Ubuntu 14.04.4 LTS Configured using: `configure --prefix=/home/a0324034/emacs' Important settings: value of $LANG: en_US.UTF-8 value of $XMODIFIERS: @im=ibus locale-coding-system: utf-8-unix Major mode: Lisp Interaction Minor modes in effect: tooltip-mode: t electric-indent-mode: t mouse-wheel-mode: t tool-bar-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t line-number-mode: t transient-mark-mode: t Recent messages: For information about GNU Emacs and the GNU system, type C-h C-a. Quit Making completion list... Load-path shadows: None found. Features: (shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util help-fns mail-prsvr mail-utils help-mode easymenu time-date tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice loaddefs button faces cus-face macroexp files text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote make-network-process dbusbind gfilenotify dynamic-setting system-font-setting font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs) Memory information: ((conses 16 72087 5028) (symbols 48 17638 0) (miscs 40 40 113) (strings 32 9276 4364) (string-bytes 1 258403) (vectors 16 8987) (vector-slots 8 383754 17180) (floats 8 64 275) (intervals 56 173 4) (buffers 960 12) (heap 1024 25044 893)) (gdb) thread apply all bt Thread 4 (Thread 0x7fe956851700 (LWP 3454)): #0 0x00007fe95d754fdd in poll () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007fe961302fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fe9613030ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fe961303129 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #4 0x00007fe961327f05 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #5 0x00007fe95da35184 in start_thread (arg=0x7fe956851700) at pthread_create.c:312 #6 0x00007fe95d76237d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 Thread 3 (Thread 0x7fe955819700 (LWP 3455)): #0 0x00007fe95d754fdd in poll () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007fe961302fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fe9613030ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fe9558211ad in ?? () from /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so #4 0x00007fe961327f05 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #5 0x00007fe95da35184 in start_thread (arg=0x7fe955819700) at pthread_create.c:312 #6 0x00007fe95d76237d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 Thread 2 (Thread 0x7fe94ffff700 (LWP 3456)): #0 0x00007fe95d754fdd in poll () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007fe961302fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fe96130330a in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fe962063336 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0 #4 0x00007fe961327f05 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #5 0x00007fe95da35184 in start_thread (arg=0x7fe94ffff700) at pthread_create.c:312 #6 0x00007fe95d76237d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 Thread 1 (Thread 0x7fe963eaca80 (LWP 3453)): #0 __GI___pthread_mutex_lock (mutex=0x13b8e00) at ../nptl/pthread_mutex_lock.c:122 ---Type to continue, or q to quit--- #1 0x00007fe961344981 in g_mutex_lock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fe961302699 in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fe961302f03 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #4 0x00007fe961303097 in g_main_context_pending () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #5 0x00007fe962746e9d in gtk_events_pending () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0 #6 0x00000000004ba4fb in XTread_socket (terminal=, hold_quit=0x7fffcff83d70) at xterm.c:7011 #7 0x00000000004ecbe1 in gobble_input () at keyboard.c:6851 #8 0x00000000004ec605 in handle_async_input () at keyboard.c:7091 #9 process_pending_signals () at keyboard.c:7105 #10 0x000000000053dd42 in Fmake_list (length=, init=12144946) at alloc.c:2637 #11 0x000000000055c7f8 in concat (nargs=nargs@entry=1, args=args@entry=0x7fffcff83ee8, target_type=Lisp_Cons, last_special=last_special@entry=false) at fns.c:588 #12 0x000000000055d321 in Fcopy_sequence (arg=19525990) at fns.c:456 #13 0x00000000004eb416 in timer_check () at keyboard.c:4572 #14 0x00000000004eb921 in readable_events (flags=1) at keyboard.c:3448 #15 0x00000000004ecce8 in get_input_pending (flags=1) at keyboard.c:6766 #16 0x00000000004f0134 in detect_input_pending_run_timers ( do_display=do_display@entry=true) at keyboard.c:9895 #17 0x0000000000595ac6 in wait_reading_process_output ( time_limit=time_limit@entry=30, nsecs=nsecs@entry=0, read_kbd=read_kbd@entry=-1, do_display=do_display@entry=true, wait_for_cell=12144946, wait_proc=wait_proc@entry=0x0, just_wait_proc=just_wait_proc@entry=0) at process.c:4702 #18 0x0000000000421a74 in sit_for (timeout=, reading=reading@entry=true, display_option=display_option@entry=1) at dispnew.c:5867 #19 0x00000000004f0e54 in read_char (commandflag=1, map=map@entry=38081766, prev_event=12144946, used_mouse_menu=used_mouse_menu@entry =0x7fffcff8472b, end_time=end_time@entry=0x0) at keyboard.c:2810 #20 0x00000000004f232f in read_key_sequence ( keybuf=keybuf@entry=0x7fffcff84800, prompt=12144946, dont_downcase_last=dont_downcase_last@entry=false, can_return_switch_frame=can_return_switch_frame@entry=true, fix_current_buffer=fix_current_buffer@entry=true, ---Type to continue, or q to quit--- prevent_redisplay=prevent_redisplay@entry=false, bufsize=30) at keyboard.c:9089 #21 0x00000000004f3f20 in command_loop_1 () at keyboard.c:1453 #22 0x0000000000555b4e in internal_condition_case ( bfun=bfun@entry=0x4f3d30 , handlers=, hfun=hfun@entry=0x4eaca0 ) at eval.c:1348 #23 0x00000000004e63de in command_loop_2 (ignore=ignore@entry=12144946) at keyboard.c:1178 #24 0x0000000000555a5b in internal_catch (tag=12192450, func=func@entry=0x4e63c0 , arg=12144946) at eval.c:1112 #25 0x00000000004ea8c7 in command_loop () at keyboard.c:1157 #26 recursive_edit_1 () at keyboard.c:778 #27 0x00000000004eabdd in Frecursive_edit () at keyboard.c:849 #28 0x0000000000417c95 in main (argc=, argv=0x7fffcff84b58) at emacs.c:1642 (gdb) xbacktrace (gdb)