bug#43177: Acknowledgement (Bug: Emacs 27.1 hangs forever in `FcCharSetSubtractCount' from '/usr/lib/libfontconfig.so.1')

[Alexander Shukaev]

Here is also a cleaner stack traceback, where I didn't issue 'USR2'
multiple times, but only one time:

Thread 1 "emacs" received signal SIGUSR2, User defined signal 2.
0x00007ffff6107823 in ?? () from /usr/lib/libfontconfig.so.1
(gdb) bt
#0 0x00007ffff6107823 in () at /usr/lib/libfontconfig.so.1
#1 0x00007ffff61079b5 in () at /usr/lib/libfontconfig.so.1
#2 0x00007ffff6107cc2 in () at /usr/lib/libfontconfig.so.1
#3 0x00007ffff6107dee in () at /usr/lib/libfontconfig.so.1
#4 0x00007ffff6108b82 in FcFontMatch () at /usr/lib/libfontconfig.so.1
#5 0x00005555558e523c in ftcrfont_open (f=0x5555564cfb40, entity=...,
pixel_size=18) at ftcrfont.c:137
#6 0x00005555558466c8 in font_open_entity (f=0x5555564cfb40,
entity=..., pixel_size=13) at font.c:2913
#7 0x0000555555848372 in font_open_for_lface (f=0x5555564cfb40,
entity=..., attrs=0x555556114b80, spec=...) at font.c:3350
#8 0x00005555558ead90 in fontset_find_font (fontset=..., c=30693,
face=0x555556114b80, charset_id=-1, fallback=false) at fontset.c:668
#9 0x00005555558eb440 in fontset_font (fontset=..., c=30693,
face=0x555556114b80, id=-1) at fontset.c:782
#10 0x00005555558ec00b in face_for_char (f=0x5555564cfb40,
face=0x555556114b80, c=30693, pos=257426, object=...) at fontset.c:996
#11 0x00005555555bd121 in FACE_FOR_CHAR (f=0x5555564cfb40,
face=0x555556114b80, character=30693, pos=257426, object=...) at
dispextern.h:1882
#12 0x00005555555db943 in get_next_display_element (it=0x7fffffff80c0)
at xdisp.c:7753
#13 0x0000555555610bda in display_line (it=0x7fffffff80c0,
cursor_vpos=1) at xdisp.c:23350
#14 0x0000555555601099 in try_window (window=..., pos=..., flags=0) at
xdisp.c:19297
#15 0x00005555555fcc94 in redisplay_window (window=...,
just_this_one_p=false) at xdisp.c:18448
#16 0x00005555555f4f38 in redisplay_window_0 (window=...) at xdisp.c:16429
#17 0x000055555581ccff in internal_condition_case_1 (bfun=0x5555555f4ef6
<redisplay_window_0>, arg=..., handlers=..., hfun=0x5555555f4ebe
<redisplay_window_error>) at eval.c:1380
#18 0x00005555555f4e92 in redisplay_windows (window=...) at xdisp.c:16409
#19 0x00005555555f4e44 in redisplay_windows (window=...) at xdisp.c:16403
#20 0x00005555555f37c4 in redisplay_internal () at xdisp.c:15877
#21 0x00005555555f1158 in redisplay () at xdisp.c:15099
#22 0x000055555573f13d in read_char (commandflag=1, map=...,
prev_event=..., used_mouse_menu=0x7fffffffd47d, end_time=0x0) at
keyboard.c:2493
#23 0x0000555555752a81 in read_key_sequence (keybuf=0x7fffffffd660,
prompt=..., dont_downcase_last=false, can_return_switch_frame=true,
fix_current_buffer=true, prevent_redisplay=false) at keyboard.c:9547
#24 0x000055555573b3d6 in command_loop_1 () at keyboard.c:1350
#25 0x000055555581cc20 in internal_condition_case (bfun=0x55555573af39
<command_loop_1>, handlers=..., hfun=0x55555573a516 <cmd_error>) at
eval.c:1356
#26 0x000055555573ab17 in command_loop_2 (ignore=...) at keyboard.c:1091
#27 0x000055555581c045 in internal_catch (tag=..., func=0x55555573aaea
<command_loop_2>, arg=...) at eval.c:1117
#28 0x000055555573aab6 in command_loop () at keyboard.c:1070
#29 0x0000555555739ff9 in recursive_edit_1 () at keyboard.c:714
#30 0x000055555573a1f5 in Frecursive_edit () at keyboard.c:786
#31 0x0000555555735f3a in main (argc=1, argv=0x7fffffffdae8) at emacs.c:2047

[Alexander Shukaev]

This is another stack when I open a file and it hangs, then I send 'ABRT':

Thread 1 "emacs" received signal SIGABRT, Aborted.
0x00007ffff5c0646f in poll () from /usr/lib/libc.so.6
(gdb) bt
#0 0x00007ffff5c0646f in poll () at /usr/lib/libc.so.6
#1 0x00007ffff6e2c7b4 in () at /usr/lib/libxcb.so.1
#2 0x00007ffff6e2cb31 in () at /usr/lib/libxcb.so.1
#3 0x00007ffff6e2a8c7 in () at /usr/lib/libxcb.so.1
#4 0x00007ffff6e2c08f in () at /usr/lib/libxcb.so.1
#5 0x00007ffff6e2c203 in xcb_wait_for_reply64 () at /usr/lib/libxcb.so.1
#6 0x00007ffff6e904b9 in _XReply () at /usr/lib/libX11.so.6
#7 0x00007ffff6e71e71 in () at /usr/lib/libX11.so.6
#8 0x00007ffff6e7254e in XLoadQueryFont () at /usr/lib/libX11.so.6
#9 0x0000555555a8d875 in xfont_supported_scripts
(display=0x555556594940, fontname=0x555564f03ae2 "-misc-cormorant
garamond-medium-i-normal--0-0-0-0-p-0-iso10646-1",
props=XIL(0x7ffff27926e5), encoding=0x7ffff23ab8d0) at xfont.c:266
#10 0x0000555555a8e5eb in xfont_list_pattern (display=0x555556594940,
pattern=0x7fffffff6450 "-*-*-*-*-*-*-*-*-*-*-*-*-iso10646-1",
registry=XIL(0x84c0), script=XIL(0x2aaa9c470db0)) at xfont.c:441
#11 0x0000555555a8e94d in xfont_list (f=0x5555564db330,
spec=XIL(0x7ffff2794475)) at xfont.c:486
#12 0x0000555555983724 in font_list_entities (f=0x5555564db330,
spec=XIL(0x555564e94e75)) at font.c:2794
#13 0x000055555598588c in font_find_for_lface (f=0x5555564db330,
attrs=0x555564a240b0, spec=XIL(0x55555688e725), c=-1) at font.c:3285
#14 0x0000555555ab4a23 in fontset_find_font
(fontset=XIL(0x555564e945c5), c=43695, face=0x555564a240b0,
charset_id=-1, fallback=false) at fontset.c:661
#15 0x0000555555ab514f in fontset_font (fontset=XIL(0x555564e93b45),
c=43695, face=0x555564a240b0, id=-1) at fontset.c:783
#16 0x0000555555ab5cff in face_for_char (f=0x5555564db330,
face=0x555564a240b0, c=43695, pos=38, object=XIL(0)) at fontset.c:997
#17 0x00005555555d0b96 in FACE_FOR_CHAR (f=0x5555564db330,
face=0x555564a240b0, character=43695, pos=38, object=XIL(0)) at
dispextern.h:1891
#18 0x00005555555f091a in get_next_display_element (it=0x7fffffff8040)
at xdisp.c:7651
#19 0x0000555555626aae in display_line (it=0x7fffffff8040,
cursor_vpos=9) at xdisp.c:23222
#20 0x0000555555617030 in try_window (window=XIL(0x5555564db575),
pos=..., flags=1) at xdisp.c:19182
#21 0x0000555555613c67 in redisplay_window (window=XIL(0x5555564db575),
just_this_one_p=false) at xdisp.c:18600
#22 0x000055555560aefd in redisplay_window_0
(window=XIL(0x5555564db575)) at xdisp.c:16314
#23 0x000055555594c082 in internal_condition_case_1 (bfun=0x55555560aebb
<redisplay_window_0>, arg=XIL(0x5555564db575),
handlers=XIL(0x7ffff279a6f3), hfun=0x55555560ae83 <redisplay_window_error>)
at eval.c:1380
#24 0x000055555560ae55 in redisplay_windows (window=XIL(0x5555564db575))
at xdisp.c:16294
#25 0x000055555560ae06 in redisplay_windows (window=XIL(0x5555624922f5))
at xdisp.c:16288
#26 0x000055555560978e in redisplay_internal () at xdisp.c:15762
#27 0x000055555560712f in redisplay () at xdisp.c:14989
#28 0x00005555557e20ca in read_char (commandflag=1,
map=XIL(0x555564e79803), prev_event=XIL(0),
used_mouse_menu=0x7fffffffd3f5, end_time=0x0) at keyboard.c:2493
#29 0x00005555557f5a94 in read_key_sequence (keybuf=0x7fffffffd5e0,
prompt=XIL(0), dont_downcase_last=false, can_return_switch_frame=true,
fix_current_buffer=true, prevent_redisplay=false) at keyboard.c:9553
#30 0x00005555557de249 in command_loop_1 () at keyboard.c:1350
#31 0x000055555594bfa5 in internal_condition_case (bfun=0x5555557ddda4
<command_loop_1>, handlers=XIL(0x90), hfun=0x5555557dd370 <cmd_error>)
at eval.c:1356
#32 0x00005555557dd97c in command_loop_2 (ignore=XIL(0)) at keyboard.c:1091
#33 0x000055555594b3ea in internal_catch (tag=XIL(0xd530),
func=0x5555557dd94e <command_loop_2>, arg=XIL(0)) at eval.c:1117
#34 0x00005555557dd919 in command_loop () at keyboard.c:1070
#35 0x00005555557dce47 in recursive_edit_1 () at keyboard.c:714
#36 0x00005555557dd046 in Frecursive_edit () at keyboard.c:786
#37 0x00005555557d313e in main (argc=1, argv=0x7fffffffda68) at emacs.c:2062

Lisp Backtrace:
"redisplay_internal (C function)" (0x0)