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

[Vladimir Nikishkin]

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 '':
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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