bug#42655: 27.1; iconify-frame on a Lucid build may stuck the frame

[Bhavin Gandhi <bhavin7392@gmail.com>]

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On Wed, 5 Aug 2020 at 00:37, Eli Zaretskii <eliz@gnu.org> wrote:
>
> > > If you now attach a debugger to Emacs, what does the backtrace show?
> >
> > Is running "gdb -i=mi -p PID" enough to generate this backtrace?
>
> Yes.  Then type "thread apply all bt" once inside GDB.  But you only
> need the -i=mi part if you invoke GDB from Emacs, via "M-x gdb RET".
> If you invoke GDB from the shell prompt, it is better to omit -i=mi.

Thanks for the suggestion, here is the backtrace at the point when Emacs
is stuck. Adding it as an attachment.

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$ gdb -p 887349
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Attaching to process 887349
[New LWP 887355]
[New LWP 887356]
[New LWP 887357]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
0x00007efde644b1a6 in pselect () from /lib64/libc.so.6
Missing separate debuginfos, use: dnf debuginfo-install Xaw3d-1.6.3-2.fc32.x86_64 alsa-lib-1.2.3.2-1.fc32.x86_64 bzip2-libs-1.0.8-2.fc32.x86_64 cairo-1.16.0-8.fc32.x86_64 cairo-gobject-1.16.0-8.fc32.x86_64 dbus-libs-1.12.20-1.fc32.x86_64 dconf-0.36.0-1.fc32.x86_64 fontconfig-2.13.92-9.fc32.x86_64 freetype-2.10.1-2.fc32.x86_64 fribidi-1.0.9-1.fc32.x86_64 gdk-pixbuf2-2.40.0-2.fc32.x86_64 giflib-5.2.1-4.fc32.x86_64 glib2-2.64.3-2.fc32.x86_64 glibc-2.31-2.fc32.x86_64 gmp-6.1.2-13.fc32.x86_64 gnutls-3.6.14-2.fc32.x86_64 graphite2-1.3.14-1.fc32.x86_64 harfbuzz-2.6.4-3.fc32.x86_64 jansson-2.12-5.fc32.x86_64 jbigkit-libs-2.1-18.fc32.x86_64 libICE-1.0.10-3.fc32.x86_64 libSM-1.2.3-5.fc32.x86_64 libX11-1.6.9-3.fc32.x86_64 libX11-xcb-1.6.9-3.fc32.x86_64 libXau-1.0.9-3.fc32.x86_64 libXext-1.3.4-3.fc32.x86_64 libXfixes-5.0.3-11.fc32.x86_64 libXinerama-1.1.4-5.fc32.x86_64 libXmu-1.1.3-3.fc32.x86_64 libXpm-3.5.13-2.fc32.x86_64 libXrender-0.9.10-11.fc32.x86_64 libXt-1.2.0-1.fc32.x86_64 libacl-2.2.53-5.fc32.x86_64 libattr-2.4.48-8.fc32.x86_64 libdatrie-0.2.9-11.fc32.x86_64 libffi-3.1-24.fc32.x86_64 libgcrypt-1.8.5-3.fc32.x86_64 libidn2-2.3.0-2.fc32.x86_64 libjpeg-turbo-2.0.4-3.fc32.x86_64 libotf-0.9.13-15.fc32.x86_64 libpng-1.6.37-3.fc32.x86_64 librsvg2-2.48.7-1.fc32.x86_64 libselinux-3.0-3.fc32.x86_64 libtiff-4.1.0-2.fc32.x86_64 libuuid-2.35.2-1.fc32.x86_64 libxcb-1.13.1-4.fc32.x86_64 libxml2-2.9.10-3.fc32.x86_64 ncurses-libs-6.1-15.20191109.fc32.x86_64 nettle-3.5.1-5.fc32.x86_64 p11-kit-0.23.20-1.fc32.x86_64 pango-1.44.7-2.fc32.x86_64 systemd-libs-245.7-1.fc32.x86_64 zlib-1.2.11-21.fc32.x86_64
(gdb) set pagination off
set pagination off
(gdb) thread apply all bt
thread apply all bt

Thread 4 (Thread 0x7efde35a1700 (LWP 887357)):
#0  0x00007efde6448b6f in poll () at /lib64/libc.so.6
#1  0x00007efde6eb2ace in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#2  0x00007efde6eb2e53 in g_main_loop_run () at /lib64/libglib-2.0.so.0
#3  0x00007efde71316aa in gdbus_shared_thread_func () at /lib64/libgio-2.0.so.0
#4  0x00007efde6edc812 in g_thread_proxy () at /lib64/libglib-2.0.so.0
#5  0x00007efde6692432 in start_thread () at /lib64/libpthread.so.0
#6  0x00007efde64539d3 in clone () at /lib64/libc.so.6

Thread 3 (Thread 0x7efde3f32700 (LWP 887356)):
#0  0x00007efde6448b6f in poll () at /lib64/libc.so.6
#1  0x00007efde6eb2ace in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#2  0x00007efde6eb2c03 in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#3  0x00007efde3f44fbd in dconf_gdbus_worker_thread () at /usr/lib64/gio/modules/libdconfsettings.so
#4  0x00007efde6edc812 in g_thread_proxy () at /lib64/libglib-2.0.so.0
#5  0x00007efde6692432 in start_thread () at /lib64/libpthread.so.0
#6  0x00007efde64539d3 in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7efde48e9700 (LWP 887355)):
#0  0x00007efde6448b6f in poll () at /lib64/libc.so.6
#1  0x00007efde6eb2ace in g_main_context_iterate.constprop () at /lib64/libglib-2.0.so.0
#2  0x00007efde6eb2c03 in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#3  0x00007efde6eb2c51 in glib_worker_main () at /lib64/libglib-2.0.so.0
#4  0x00007efde6edc812 in g_thread_proxy () at /lib64/libglib-2.0.so.0
#5  0x00007efde6692432 in start_thread () at /lib64/libpthread.so.0
#6  0x00007efde64539d3 in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7efde5a3e080 (LWP 887349)):
#0  0x00007efde644b1a6 in pselect () at /lib64/libc.so.6
#1  0x00000000008b7277 in really_call_select (arg=0x7ffc18d6b460) at ../../src/thread.c:586
#2  0x000000000073c366 in flush_stack_call_func (func=0x8b71dd <really_call_select>, arg=0x7ffc18d6b460) at ../../src/alloc.c:4951
#3  0x00000000008b732d in thread_select (func=0x4161f0 <pselect@plt>, max_fds=7, rfds=0x7ffc18d6b990, wfds=0x7ffc18d6b910, efds=0x0, timeout=0x7ffc18d6bc70, sigmask=0x0) at ../../src/thread.c:616
#4  0x000000000091323b in xg_select (fds_lim=7, rfds=0x7ffc18d6bd10, wfds=0x7ffc18d6bc90, efds=0x0, timeout=0x7ffc18d6bc70, sigmask=0x0) at ../../src/xgselect.c:117
#5  0x0000000000832699 in wait_reading_process_output (time_limit=0, nsecs=0, read_kbd=-1, do_display=true, wait_for_cell=..., wait_proc=0x0, just_wait_proc=0) at ../../src/process.c:5571
#6  0x0000000000641d68 in kbd_buffer_get_event (kbp=0x7ffc18d6bfe8, used_mouse_menu=0x7ffc18d6c67f, end_time=0x0) at ../../src/keyboard.c:3866
#7  0x000000000063c86a in read_event_from_main_queue (end_time=0x0, local_getcjmp=0x7ffc18d6c420, used_mouse_menu=0x7ffc18d6c67f) at ../../src/keyboard.c:2156
#8  0x000000000063cbf9 in read_decoded_event_from_main_queue (end_time=0x0, local_getcjmp=0x7ffc18d6c420, prev_event=..., used_mouse_menu=0x7ffc18d6c67f) at ../../src/keyboard.c:2220
#9  0x000000000063ed11 in read_char (commandflag=1, map=..., prev_event=..., used_mouse_menu=0x7ffc18d6c67f, end_time=0x0) at ../../src/keyboard.c:2830
#10 0x000000000065036d in read_key_sequence (keybuf=0x7ffc18d6c820, prompt=..., dont_downcase_last=false, can_return_switch_frame=true, fix_current_buffer=true, prevent_redisplay=false) at ../../src/keyboard.c:9553
#11 0x000000000063a187 in command_loop_1 () at ../../src/keyboard.c:1350
#12 0x0000000000796ad7 in internal_condition_case (bfun=0x639d27 <command_loop_1>, handlers=..., hfun=0x639390 <cmd_error>) at ../../src/eval.c:1356
#13 0x0000000000639937 in command_loop_2 (ignore=...) at ../../src/keyboard.c:1091
#14 0x0000000000795fee in internal_catch (tag=..., func=0x63990e <command_loop_2>, arg=...) at ../../src/eval.c:1117
#15 0x00000000006398da in command_loop () at ../../src/keyboard.c:1070
#16 0x0000000000638ea4 in recursive_edit_1 () at ../../src/keyboard.c:714
#17 0x0000000000639085 in Frecursive_edit () at ../../src/keyboard.c:786
#18 0x000000000062f83e in main (argc=2, argv=0x7ffc18d6cd28) at ../../src/emacs.c:2062