bug#39081: 26.3; Emacs hangs if external SCIM input method is killed

[Vladimir Nikishkin]

Sorry, my debugging skills are too poor.

So I attached gdb to Emacs, cont'd, then killed scim, and then
interrupted Emacs by issuing C-c in the gdb prompt,
and then collected a stack trace. I am not sure I am doing something
meaningful, as this is the first time I use gdb:
Here's the stack trace:

Thread 1 "emacs" received signal SIGINT, Interrupt.
0x00007f5e0c908e9f in poll () from /lib64/libc.so.6
(gdb) thread apply all bt

Thread 3 (Thread 0x7f5e093b9700 (LWP 1967)):
#0  0x00007f5e0c908e9f in poll () at /lib64/libc.so.6
#1  0x00007f5e0e70dcee in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007f5e0e70e053 in g_main_loop_run () at /usr/lib64/libglib-2.0.so.0
#3  0x00007f5e0e943666 in  () at /usr/lib64/libgio-2.0.so.0
#4  0x00007f5e0e73598d in  () at /usr/lib64/libglib-2.0.so.0
#5  0x00007f5e0ced606b in start_thread () at /lib64/libpthread.so.0
#6  0x00007f5e0c91472f in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7f5e0a3d9700 (LWP 1966)):
#0  0x00007f5e0c908e9f in poll () at /lib64/libc.so.6
#1  0x00007f5e0e70dcee in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007f5e0e70de0f in g_main_context_iteration () at
/usr/lib64/libglib-2.0.so.0
#3  0x00007f5e0e70de61 in  () at /usr/lib64/libglib-2.0.so.0
#4  0x00007f5e0e73598d in  () at /usr/lib64/libglib-2.0.so.0
#5  0x00007f5e0ced606b in start_thread () at /lib64/libpthread.so.0
#6  0x00007f5e0c91472f in clone () at /lib64/libc.so.6

--Type <RET> for more, q to quit, c to continue without paging--
Thread 1 (Thread 0x7f5e0ae93c80 (LWP 1965)):
#0  0x00007f5e0c908e9f in poll () at /lib64/libc.so.6
#1  0x00007f5e0e533d17 in  () at /usr/lib64/libxcb.so.1
#2  0x00007f5e0e53580a in xcb_wait_for_event () at /usr/lib64/libxcb.so.1
#3  0x00007f5e0e598328 in _XReadEvents () at /usr/lib64/libX11.so.6
#4  0x00007f5e0e5807f5 in XIfEvent () at /usr/lib64/libX11.so.6
#5  0x00007f5e0e5c621f in  () at /usr/lib64/libX11.so.6
#6  0x00007f5e0e5c6bc2 in  () at /usr/lib64/libX11.so.6
#7  0x00007f5e0e5c6e5c in _XimRead () at /usr/lib64/libX11.so.6
#8  0x00007f5e0e5b5bdb in  () at /usr/lib64/libX11.so.6
#9  0x00007f5e0e5a4f15 in XSetICValues () at /usr/lib64/libX11.so.6
#10 0x00000000004e0beb in xic_set_preeditarea (w=w@entry=0x1328920,
x=x@entry=163, y=y@entry=84) at xfns.c:2785
#11 0x00000000004ce685 in x_draw_window_cursor (w=0x1328920,
glyph_row=0x1adee70, x=163, y=84, cursor_type=<optimized out>,
cursor_width=<optimized out>, on_p=<optimized out>,
active_p=<optimized out>) at xterm.c:9700
#12 0x000000000046b4e7 in display_and_set_cursor (w=0x1328920,
on=<optimized out>, hpos=11, vpos=3, x=163, y=<optimized out>) at
xdisp.c:31324
#13 0x000000000046be46 in update_window_cursor (w=<optimized out>,
on=<optimized out>) at xdisp.--Type <RET> for more, q to quit, c to
continue without paging--
c:31359
#14 0x000000000046beaa in update_cursor_in_window_tree (w=0x1328920,
on_p=on_p@entry=true) at xdisp.c:31377
#15 0x000000000046bed9 in update_cursor_in_window_tree (w=0x2879ea0,
on_p=on_p@entry=true) at lisp.h:730
#16 0x000000000046bf01 in gui_update_cursor (f=f@entry=0x13245c0,
on_p=on_p@entry=true) at lisp.h:730
#17 0x00000000004d3473 in x_frame_highlight (f=<optimized out>) at xterm.c:4488
#18 0x00000000004d3473 in x_frame_rehighlight (dpyinfo=<optimized
out>, dpyinfo=<optimized out>) at xterm.c:4860
#19 0x00000000004d35c4 in x_focus_changed (type=<optimized out>,
state=2, dpyinfo=0x110b680, frame=0x13245c0, bufp=0x7ffc81d0f240) at
xterm.c:4550
#20 0x00000000004d49c5 in handle_one_xevent (dpyinfo=0x110b680,
event=0x7ffc81d0f820, finish=0x9c35d0 <current_finish>,
hold_quit=0x7ffc81d0fa70) at xterm.c:8802
#21 0x00000000004d6eee in event_handler_gdk (gxev=0x7ffc81d0f820,
ev=<optimized out>, data=<optimized out>) at xterm.c:7773
#22 0x00007f5e0ec4999f in  () at /usr/lib64/libgdk-3.so.0
#23 0x00007f5e0ec49cbb in  () at /usr/lib64/libgdk-3.so.0
#24 0x00007f5e0ec14030 in gdk_display_get_event () at /usr/lib64/libgdk-3.so.0
--Type <RET> for more, q to quit, c to continue without paging--
#25 0x00007f5e0ec49a32 in  () at /usr/lib64/libgdk-3.so.0
#26 0x00007f5e0e70db2d in g_main_context_dispatch () at
/usr/lib64/libglib-2.0.so.0
#27 0x00007f5e0e70dd80 in  () at /usr/lib64/libglib-2.0.so.0
#28 0x00007f5e0e70de0f in g_main_context_iteration () at
/usr/lib64/libglib-2.0.so.0
#29 0x00007f5e0eee2105 in gtk_main_iteration () at /usr/lib64/libgtk-3.so.0
#30 0x00000000004cabf3 in XTread_socket (terminal=<optimized out>,
hold_quit=0x7ffc81d0fa70) at xterm.c:9386
#31 0x00000000004fd5f2 in gobble_input () at keyboard.c:6891
#32 0x00000000004fdb95 in handle_async_input () at keyboard.c:7128
#33 0x00000000004fdb95 in process_pending_signals () at keyboard.c:7142
#34 0x0000000000572d6b in list_length (list=0x2287cb3) at lisp.h:1449
#35 0x0000000000572ea8 in Flength (sequence=<optimized out>) at fns.c:129
#36 0x000000000057300d in concat (nargs=1, args=0x7ffc81d0fc08,
target_type=Lisp_Cons, last_special=<optimized out>) at fns.c:680
#37 0x0000000000573d33 in Fcopy_sequence (arg=<optimized out>) at lisp.h:745
#38 0x00000000004fc83c in timer_check () at keyboard.c:4387
#39 0x00000000004fcd45 in readable_events (flags=flags@entry=1) at
keyboard.c:3397
#40 0x00000000004fd758 in get_input_pending (flags=flags@entry=1) at
keyboard.c:6809
#41 0x0000000000500638 in detect_input_pending_run_timers
(do_display=do_display@entry=true) at --Type <RET> for more, q to
quit, c to continue without paging--
keyboard.c:10367
#42 0x00000000005a7024 in wait_reading_process_output
(time_limit=time_limit@entry=15, nsecs=nsecs@entry=0,
read_kbd=read_kbd@entry=-1, do_display=do_display@entry=true,
wait_for_cell=wait_for_cell@entry=0x0, wait_proc=wait_proc@entry=0x0,
just_wait_proc=0) at process.c:5707
#43 0x000000000042d82f in sit_for (timeout=timeout@entry=0x3e,
reading=reading@entry=true, display_option=display_option@entry=1) at
lisp.h:1032
#44 0x00000000005032e8 in read_char (commandflag=1, map=0x2c9f583,
prev_event=0x0, used_mouse_menu=0x7ffc81d107ab, end_time=0x0) at
lisp.h:1147
#45 0x000000000050380e in read_key_sequence (keybuf=<optimized out>,
prompt=0x0, dont_downcase_last=<optimized out>,
can_return_switch_frame=true, fix_current_buffer=true,
prevent_redisplay=<optimized out>) at keyboard.c:9553
#46 0x0000000000504e8e in command_loop_1 () at lisp.h:1032
#47 0x0000000000568d37 in internal_condition_case
(bfun=bfun@entry=0x504cb0 <command_loop_1>,
handlers=handlers@entry=0x90, hfun=hfun@entry=0x4fbee0 <cmd_error>) at
eval.c:1355
#48 0x00000000004f6cfc in command_loop_2 (ignore=ignore@entry=0x0) at
lisp.h:1032
#49 0x0000000000568c91 in internal_catch (tag=tag@entry=0xd4d0,
func=func@entry=0x4f6ce0 <command_loop_2>, arg=arg@entry=0x0) at
eval.c:1116
#50 0x00000000004f6ca4 in command_loop () at lisp.h:1032
#51 0x00000000004fbaf6 in recursive_edit_1 () at keyboard.c:714
--Type <RET> for more, q to quit, c to continue without paging--
#52 0x00000000004fbe20 in Frecursive_edit () at keyboard.c:786
#53 0x0000000000423f25 in main (argc=1, argv=0x7ffc81d10ca8) at emacs.c:2054
(gdb)

вс, 12 янв. 2020 г. в 14:40, Vladimir Nikishkin <lockywolf@gmail.com>:
>
> Below is the thread apply all bt result for a hanged, unoptimized,
> Emacs. I attached gdb after start, but before killing SCIM:
>
> lockywolf@delllaptop:~$ pgrep emacs
> 1437
> lockywolf@delllaptop:~$ gdb -p $(pgrep emacs)
> /usr/share/gdb/python/gdb/command/prompt.py:48: SyntaxWarning: "is
> not" with a literal. Did you mean "!="?
>   if self.value is not '':
> /usr/share/gdb/python/gdb/command/prompt.py:60: SyntaxWarning: "is
> not" with a literal. Did you mean "!="?
>   if self.value is not '':
> GNU gdb (GDB) 8.3.1
> Copyright (C) 2019 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
> Type "show copying" and "show warranty" for details.
> This GDB was configured as "x86_64-slackware-linux".
> Type "show configuration" for configuration details.
> For bug reporting instructions, please see:
> <http://www.gnu.org/software/gdb/bugs/>.
> Find the GDB manual and other documentation resources online at:
>     <http://www.gnu.org/software/gdb/documentation/>.
>
> For help, type "help".
> Type "apropos word" to search for commands related to "word".
> Attaching to process 1437
> [New LWP 1438]
> [New LWP 1439]
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib64/libthread_db.so.1".
> 0x00007f395c99807e in pselect () from /lib64/libc.so.6
> (gdb) thread apply all bt
>
> Thread 3 (Thread 0x7f3959446700 (LWP 1439)):
> #0  0x00007f395c995e9f in poll () at /lib64/libc.so.6
> #1  0x00007f395e79acee in  () at /usr/lib64/libglib-2.0.so.0
> #2  0x00007f395e79b053 in g_main_loop_run () at /usr/lib64/libglib-2.0.so.0
> #3  0x00007f395e9d0666 in  () at /usr/lib64/libgio-2.0.so.0
> #4  0x00007f395e7c298d in  () at /usr/lib64/libglib-2.0.so.0
> #5  0x00007f395cf6306b in start_thread () at /lib64/libpthread.so.0
> #6  0x00007f395c9a172f in clone () at /lib64/libc.so.6
>
> Thread 2 (Thread 0x7f395a466700 (LWP 1438)):
> #0  0x00007f395c995e9f in poll () at /lib64/libc.so.6
> #1  0x00007f395e79acee in  () at /usr/lib64/libglib-2.0.so.0
> #2  0x00007f395e79ae0f in g_main_context_iteration () at
> /usr/lib64/libglib-2.0.so.0
> #3  0x00007f395e79ae61 in  () at /usr/lib64/libglib-2.0.so.0
> #4  0x00007f395e7c298d in  () at /usr/lib64/libglib-2.0.so.0
> #5  0x00007f395cf6306b in start_thread () at /lib64/libpthread.so.0
> --Type <RET> for more, q to quit, c to continue without paging--
> #6  0x00007f395c9a172f in clone () at /lib64/libc.so.6
>
> Thread 1 (Thread 0x7f395af20c80 (LWP 1437)):
> #0  0x00007f395c99807e in pselect () at /lib64/libc.so.6
> #1  0x00000000005c5bd0 in really_call_select (arg=0x7ffff4d2e960) at
> thread.c:586
> #2  0x00000000005c66a7 in thread_select (func=<optimized out>,
> max_fds=max_fds@entry=20, rfds=rfds@entry=0x7ffff4d2ea10,
> wfds=wfds@entry=0x7ffff4d2ea90, efds=efds@entry=0x0,
> timeout=timeout@entry=0x7ffff4d2f010, sigmask=0x0) at thread.c:616
> #3  0x00000000005e0e34 in xg_select (fds_lim=20,
> rfds=rfds@entry=0x7ffff4d2f120, wfds=wfds@entry=0x7ffff4d2f1a0,
> efds=efds@entry=0x0, timeout=timeout@entry=0x7ffff4d2f010,
> sigmask=sigmask@entry=0x0) at xgselect.c:117
> #4  0x00000000005a6db3 in wait_reading_process_output
> (time_limit=time_limit@entry=15, nsecs=nsecs@entry=0,
> read_kbd=read_kbd@entry=-1, do_display=do_display@entry=true,
> wait_for_cell=wait_for_cell@entry=0x0, wait_proc=wait_proc@entry=0x0,
> just_wait_proc=0) at process.c:5571
> #5  0x000000000042d82f in sit_for (timeout=timeout@entry=0x3e,
> reading=reading@e--Type <RET> for more, q to quit, c to continue
> without paging--
> ntry=true, display_option=display_option@entry=1) at lisp.h:1032
> #6  0x00000000005032e8 in read_char (commandflag=1, map=0x3f872e3,
> prev_event=0x0, used_mouse_menu=0x7ffff4d2f9db, end_time=0x0) at
> lisp.h:1147
> #7  0x000000000050380e in read_key_sequence (keybuf=<optimized out>,
> prompt=0x0, dont_downcase_last=<optimized out>,
> can_return_switch_frame=true, fix_current_buffer=true,
> prevent_redisplay=<optimized out>) at keyboard.c:9553
> #8  0x0000000000504e8e in command_loop_1 () at lisp.h:1032
> #9  0x0000000000568d37 in internal_condition_case
> (bfun=bfun@entry=0x504cb0 <command_loop_1>,
> handlers=handlers@entry=0x90, hfun=hfun@entry=0x4fbee0 <cmd_error>) at
> eval.c:1355
> #10 0x00000000004f6cfc in command_loop_2 (ignore=ignore@entry=0x0) at
> lisp.h:1032
> #11 0x0000000000568c91 in internal_catch (tag=tag@entry=0xd4d0,
> func=func@entry=0x4f6ce0 <command_loop_2>, arg=arg@entry=0x0) at
> eval.c:1116
> #12 0x00000000004f6ca4 in command_loop () at lisp.h:1032
> #13 0x00000000004fbaf6 in recursive_edit_1 () at keyboard.c:714
> #14 0x00000000004fbe20 in Frecursive_edit () at keyboard.c:786
> #15 0x0000000000423f25 in main (argc=1, argv=0x7ffff4d2fed8) at emacs.c:2054
> (gdb)
>
> вс, 12 янв. 2020 г. в 14:34, Eli Zaretskii <eliz@gnu.org>:
> >
> > On January 12, 2020 8:05:06 AM GMT+02:00, Vladimir Nikishkin 
> > <lockywolf@gmail.com> wrote:
> > > Okay, I rebuild Emacs from git with debug information, and after a few
> > > attempts, Emacs crashed, printing "This is a GTK bug".
> > > I am not sure why optimized Emacs hangs instead of crashing.
> > > Maybe this bug can be closed (or maybe there is an interleaving
> > > between two bugs)
> >
> > Please run Emacs under GDB, and when it crashes, please show the backtrace. 
> >  I'd like to see the details of this crash, perhaps this is some known 
> > problem.  Those details might also explain the difference in behavior 
> > between the optimized and debug builds.
> >
> > Thanks.
>
>
>
> --
> Yours sincerely, Vladimir Nikishkin



-- 
Yours sincerely, Vladimir Nikishkin