--- Begin Message ---
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Subject: |
emacs signals under gdb - [Re: connecting to a lost server process |
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Date: |
Sun, 14 Jul 2019 17:30:52 +0530 |
[sorry if this is not the correct bug format, I'm replying to a message
on gnu.emacs.help]
* Eli Zaretskii <address@hidden> :
Wrote on Fri, 12 Jul 2019 10:54:28 +0300:
>> Date: 12 Jul 2019 06:20:57 -0000
>> From: Madhu <address@hidden>
>>
>> Earlier it used to be possible to gdb attach to the emacs process and
>> to restart the server. Something like
>> Feval(Fcar(Fread_from_string(build_string("(server-start)"),Qnil,Qnil)),Qnil)
>> But for some time now that route hits a
>> terminate_due_to_signal. (Apparently make-network-process tries to
>> signal an error which calls emacs_abort which ends the show)
>
> Please report a bug with the details of that crash, it may or may not
> be a bug.
I noticed a couple of different failure modes but this problem seems to
be related to pselect. I'm appending one backtrace. Note within the
transcript emacs is started with
args: -Q --eval '(progn (load-library "custom") (load-library "server") (setq
server-name "emacs-test"))'
After emacs is started by gdb I send it a TSTP to make it enter the
debugger.
Reading symbols from emacs-27-athena...
SIGINT is used by the debugger.
Are you sure you want to change it? (y or n) [answered Y; input not from
terminal]
DISPLAY = :0
TERM = dumb
Breakpoint 1 at 0x41657c: file
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/emacs.c,
line 377.
Breakpoint 2 at 0x4c4b20: file
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/xterm.c,
line 10041.
(gdb) set args -Q --eval '(progn (load-library "custom") (load-library
"server") (setq server-name "emacs-test"))'
(gdb) r
Starting program: /usr/bin/emacs-27-athena -Q --eval '(progn (load-library
"custom") (load-library "server") (setq server-name "emacs-test"))'
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
desired fingerprint:
4f725133cab4014b55eba47d01b62b95cf9f5c2332a7167947770875a0da328e
found fingerprint:
87155434115e758f6db5abaf07c65b6b14264b02baec22545448e62abb35872f
[New Thread 0x7ffff4b5b700 (LWP 10762)]
Thread 1 "emacs-27-athena" received signal SIGTSTP, Stopped (user).
0x00007ffff6b47926 in __pselect (nfds=7, readfds=0x7fffffffcf50,
writefds=0x7fffffffcfd0, exceptfds=0x0, timeout=<optimized out>,
sigmask=<optimized out>) at ../sysdeps/unix/sysv/linux/pselect.c:69
69 result = CALL_PSELECT6 (nfds, readfds, writefds, exceptfds, timeout,
(gdb) p
Feval(Fcar(Fread_from_string(build_string("(server-start)"),Qnil,Qnil)),Qnil)
Thread 1 "emacs-27-athena" hit Breakpoint 1, terminate_due_to_signal (
sig=sig@entry=6, backtrace_limit=backtrace_limit@entry=40)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/emacs.c:377
377
The program being debugged stopped while in a function called from GDB.
Evaluation of the expression containing the function
(Feval) will be abandoned.
When the function is done executing, GDB will silently stop.
(gdb) back
#0 terminate_due_to_signal (sig=sig@entry=6,
backtrace_limit=backtrace_limit@entry=40)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/emacs.c:377
#1 0x0000000000416a50 in emacs_abort ()
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/sysdep.c:2437
#2 0x0000000000418a90 in signal_or_quit (error_symbol=XIL(0x58e0),
data=XIL(0xdd5663), keyboard_quit=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:1595
#3 0x0000000000418aa9 in Fsignal (error_symbol=<optimized out>,
data=data@entry=XIL(0xdd5663))
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:1565
#4 0x0000000000417118 in xsignal (data=XIL(0xdd5663),
error_symbol=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/lisp.h:4101
#5 report_file_errno (string=<optimized out>, name=name@entry=XIL(0xdd55f3),
errorno=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/fileio.c:222
#6 0x000000000041a663 in connect_network_socket (proc=XIL(0xd7f415),
addrinfos=<optimized out>, use_external_socket_p=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/process.c:3633
#7 0x00000000005a2cc6 in Fmake_network_process (nargs=<optimized out>,
args=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/process.c:4246
#8 0x000000000055f533 in Ffuncall (nargs=11, args=args@entry=0x7fffffffc298)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/lisp.h:2087
#9 0x0000000000599e60 in exec_byte_code (bytestr=<optimized out>,
vector=<optimized out>, maxdepth=<optimized out>,
args_template=<optimized out>, nargs=<optimized out>,
args=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/bytecode.c:633
#10 0x000000000055f4bf in Ffuncall (nargs=2, args=args@entry=0x7fffffffc688)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:2817
#11 0x0000000000599e60 in exec_byte_code (bytestr=<optimized out>,
vector=<optimized out>, maxdepth=<optimized out>,
args_template=<optimized out>, nargs=<optimized out>,
args=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/bytecode.c:633
#12 0x0000000000560ec1 in apply_lambda (fun=XIL(0xaee9f5),
args=<optimized out>, count=count@entry=6)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:2935
#13 0x00000000005611f3 in eval_sub (form=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:2349
#14 0x0000000000562d89 in Feval (form=XIL(0xdd5543), lexical=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:2103
#15 <function called from gdb>
#16 0x00007ffff6b47926 in __pselect (nfds=7, readfds=0x7fffffffcf50,
writefds=0x7fffffffcfd0, exceptfds=0x0, timeout=<optimized out>,
sigmask=<optimized out>) at ../sysdeps/unix/sysv/linux/pselect.c:69
#17 0x00000000005bead0 in really_call_select (arg=0x7fffffffce80)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/thread.c:586
#18 0x00000000005bf3e7 in thread_select (func=<optimized out>,
max_fds=max_fds@entry=7, rfds=rfds@entry=0x7fffffffcf50,
wfds=wfds@entry=0x7fffffffcfd0, efds=efds@entry=0x0,
timeout=timeout@entry=0x7fffffffd550, sigmask=0x0)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/thread.c:616
#19 0x00000000005dd722 in xg_select (fds_lim=7,
rfds=rfds@entry=0x7fffffffd660, wfds=wfds@entry=0x7fffffffd6e0,
efds=efds@entry=0x0, timeout=timeout@entry=0x7fffffffd550,
sigmask=sigmask@entry=0x0)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/xgselect.c:117
#20 0x00000000005a3fa4 in wait_reading_process_output (
time_limit=time_limit@entry=0, nsecs=nsecs@entry=0,
read_kbd=read_kbd@entry=-1, do_display=true,
wait_for_cell=wait_for_cell@entry=XIL(0), wait_proc=wait_proc@entry=0x0,
just_wait_proc=0)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/process.c:5440
#21 0x00000000004f15c9 in kbd_buffer_get_event (end_time=0x0,
used_mouse_menu=0x7fffffffdebb, kbp=<synthetic pointer>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/lisp.h:1058
#22 read_event_from_main_queue (used_mouse_menu=0x7fffffffdebb,
local_getcjmp=0x7fffffffdb50, end_time=0x0)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/keyboard.c:2138
#23 read_decoded_event_from_main_queue (used_mouse_menu=<optimized out>,
prev_event=<optimized out>, local_getcjmp=<optimized out>,
end_time=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/keyboard.c:2202
#24 read_char (commandflag=1, map=XIL(0xdb7d13), prev_event=XIL(0),
used_mouse_menu=0x7fffffffdebb, end_time=0x0)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/keyboard.c:2810
#25 0x00000000004f3256 in read_key_sequence (keybuf=<optimized out>,
prompt=XIL(0), dont_downcase_last=<optimized out>,
can_return_switch_frame=true, fix_current_buffer=true,
prevent_redisplay=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/keyboard.c:9125
#26 0x00000000004f4b8e in command_loop_1 ()
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/lisp.h:1058
#27 0x000000000055e857 in internal_condition_case (
bfun=bfun@entry=0x4f49b0 <command_loop_1>,
handlers=handlers@entry=XIL(0x50d0), hfun=hfun@entry=0x4ec060 <cmd_error>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:1352
#28 0x00000000004e703c in command_loop_2 (ignore=ignore@entry=XIL(0))
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/lisp.h:1058
#29 0x000000000055e7b1 in internal_catch (tag=tag@entry=XIL(0xc9f0),
func=func@entry=0x4e7020 <command_loop_2>, arg=arg@entry=XIL(0))
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/eval.c:1113
#30 0x00000000004e6fe4 in command_loop ()
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/lisp.h:1058
#31 0x00000000004ebc76 in recursive_edit_1 ()
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/keyboard.c:714
#32 0x00000000004ebfa0 in Frecursive_edit ()
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/keyboard.c:786
#33 0x000000000041c2c3 in main (argc=4, argv=0x7fffffffe338)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/emacs.c:2126
Lisp Backtrace:
"make-network-process" (0xffffc2a0)
"server-running-p" (0xffffc690)
"server-start" (0xffffcbc0)
(gdb) up 5
#5 report_file_errno (string=<optimized out>, name=name@entry=XIL(0xdd55f3),
errorno=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/fileio.c:222
222 xsignal (Fcar (data), Fcdr (data));
(gdb) pp data
(file-missing "make client process failed" "No such file or directory" :name
"server-client-test" :family local :server nil :noquery t :service
"/dev/shm/madhu/emacs/emacs-test")
(gdb) up
#6 0x000000000041a663 in connect_network_socket (proc=XIL(0xd7f415),
addrinfos=<optimized out>, use_external_socket_p=<optimized out>)
at
/var/tmp/portage/app-editors/emacs-27.0.50-r3/work/emacs-27.0.50/src/process.c:3633
3633 unbind_to (count, Qnil);
(gdb)
Additional notes:
- make-network-process signals a (file-missing "make client process failed" "No
such file or directory" :name "server-client-test" :family local :server nil
:noquery t :service "/dev/shm/madhu/emacs/emacs-test")
which is not supposed to happen since the file would be created by the
system call to socket. I suspect a wrong error is being reported
because of some problem with pselect (which is interrupted when we
enter gdb)
- load custom.el to try to avoid an unrelated emacs-abort which
otherwise seems to happen from within the custom mechanism
- another unrelated emacs-bug. M-x gud-gdb -- emacs .. with the above
arg line fails to pass the quoted arguments to gdb.
--- End Message ---