bug#65325: "make check" hangs on Cygwin

[Bruno Haible]

Eli Zaretskii wrote:
> I'm not sure when and how this could be addressed.

In case it helps, here are the gdb stack traces from the two hanging processes.


Stack traces in emacs.exe:

Attaching to program `/home/bruno/emacs/build-cygwin64/src/emacs', process 1000
[New Thread 1000.0xb58]
[New Thread 1000.0xe8c]
[New Thread 1000.0x1248]
[New Thread 1000.0x1594]
[New Thread 1000.0x84c]
[New Thread 1000.0x8e8]
[New Thread 1000.0xd98]
[New Thread 1000.0x16e4]
0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) info threads
  Id   Target Id         Frame
* 8    Thread 1000.0x16e4 0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  7    Thread 1000.0xd98 0x00007ffbfbfad094 in ntdll!ZwWaitForSingleObject ()
   from /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  6    Thread 1000.0x8e8 0x00007ffbfbfad094 in ntdll!ZwWaitForSingleObject ()
   from /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  5    Thread 1000.0x84c 0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  4    Thread 1000.0x1594 0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  3    Thread 1000.0x1248 0x00007ffbfbfad734 in ntdll!ZwFsControlFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  2    Thread 1000.0xe8c 0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  1    Thread 1000.0xb58 0x00007ffbfbfadb64 in ntdll!ZwWaitForMultipleObjects ()
   from /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) thread 1
[Switching to thread 1 (Thread 1000.0xb58)]
#0  0x00007ffbfbfadb64 in ntdll!ZwWaitForMultipleObjects () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfadb64 in ntdll!ZwWaitForMultipleObjects () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf99a1be0 in WaitForMultipleObjectsEx () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x00007ffbf99a1ade in WaitForMultipleObjects () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#3  0x0000000180045b39 in cygwait(void*, _LARGE_INTEGER*, unsigned int) () from 
/usr/bin/cygwin1.dll
#4  0x00000001800a0d8d in fhandler_pty_slave::read(void*, unsigned long&) () 
from /usr/bin/cygwin1.dll
#5  0x0000000180131472 in read () from /usr/bin/cygwin1.dll
#6  0x00000001801cbe23 in _read_r () from /usr/bin/cygwin1.dll
#7  0x000000018019185c in __sread () from /usr/bin/cygwin1.dll
#8  0x0000000180190787 in __srefill_r () from /usr/bin/cygwin1.dll
#9  0x0000000180190953 in __srget_r () from /usr/bin/cygwin1.dll
#10 0x00000001801197eb in _sigfe () from /usr/bin/cygwin1.dll
#11 0x00000001004af92d in __sgetc_r (__p=0x1801fc7b8 <reent_data+1336>, 
__ptr=0xffffd680) at /usr/include/stdio.h:671
#12 _getchar_unlocked () at /usr/include/stdio.h:747
#13 kbd_buffer_get_event (used_mouse_menu=<optimized out>, end_time=0xffffa8f0, 
kbp=<synthetic pointer>)
    at ../../src/keyboard.c:3978
#14 read_event_from_main_queue (used_mouse_menu=<optimized out>, 
local_getcjmp=<optimized out>,
    end_time=<optimized out>) at ../../src/keyboard.c:2309
#15 read_decoded_event_from_main_queue (used_mouse_menu=<optimized out>, 
prev_event=<optimized out>,
    local_getcjmp=<optimized out>, end_time=<optimized out>) at 
../../src/keyboard.c:2372
#16 read_char (commandflag=<optimized out>, commandflag@entry=0, map=<optimized 
out>, map@entry=0x0,
    prev_event=<optimized out>, prev_event@entry=0x30, 
used_mouse_menu=<optimized out>, used_mouse_menu@entry=0x0,
    end_time=<optimized out>) at ../../src/keyboard.c:3003
#17 0x0000000100553ac2 in read_filtered_event 
(no_switch_frame=no_switch_frame@entry=false,
    ascii_required=ascii_required@entry=false, 
error_nonascii=error_nonascii@entry=false,
    input_method=input_method@entry=false, seconds=seconds@entry=0x6ffff4c8337) 
at ../../src/lread.c:849
#18 0x0000000100553ebd in Fread_event (prompt=0x0, inherit_input_method=0x0, 
seconds=0x6ffff4c8337)
    at ../../src/lread.c:999
#19 0x000000010056b52a in exec_byte_code (fun=<optimized out>, 
fun@entry=0x6ffff871455, args_template=<optimized out>,
    nargs=<optimized out>, nargs@entry=-5260204364768739327, args=<optimized 
out>, args@entry=0x6ffff040850)
    at ../../src/bytecode.c:815
#20 0x000000010052ac4e in fetch_and_exec_byte_code (args=0x6ffff040850, 
nargs=-5260204364768739327,
    args_template=<optimized out>, fun=0x6ffff871455) at ../../src/eval.c:3094
#21 funcall_lambda (fun=0x6ffff871455, nargs=-5260204364768739327, 
nargs@entry=1,
    arg_vector=arg_vector@entry=0x6ffff040850) at ../../src/eval.c:3166
#22 0x000000010052b2d8 in funcall_general (fun=<optimized out>, 
numargs=numargs@entry=1, args=args@entry=0x6ffff040850)
    at ../../src/eval.c:2970
#23 0x000000010052b49d in Ffuncall (nargs=nargs@entry=2, 
args=args@entry=0x6ffff040848) at ../../src/eval.c:3008
#24 0x000000010052b9d3 in Fapply (nargs=2, args=0x6ffff040848) at 
../../src/eval.c:2636
#25 0x000000010056b52a in exec_byte_code (fun=<optimized out>, 
fun@entry=0x600296135, args_template=<optimized out>,
    nargs=<optimized out>, nargs@entry=-864691128455135230, args=<optimized 
out>, args@entry=0xffffacb8)
    at ../../src/bytecode.c:815
#26 0x000000010052ac4e in fetch_and_exec_byte_code (args=0xffffacb8, 
nargs=-864691128455135230,
    args_template=<optimized out>, fun=0x600296135) at ../../src/eval.c:3094
#27 funcall_lambda (fun=0x600296135, nargs=-864691128455135230, nargs@entry=2, 
arg_vector=arg_vector@entry=0xffffacb8)
    at ../../src/eval.c:3166
#28 0x000000010052b2d8 in funcall_general (fun=<optimized out>, 
numargs=numargs@entry=2, args=args@entry=0xffffacb8)
    at ../../src/eval.c:2970
#29 0x000000010052b49d in Ffuncall (nargs=nargs@entry=3, 
args=args@entry=0xffffacb0) at ../../src/eval.c:3008
#30 0x000000010052b860 in Fapply (nargs=nargs@entry=2, 
args=args@entry=0xffffad60) at ../../src/eval.c:2679
#31 0x000000010052ba8c in apply1 (fn=<optimized out>, arg=<optimized out>) at 
../../src/eval.c:2895
#32 0x0000000100528bf5 in internal_condition_case_1 
(bfun=bfun@entry=0x10056e710 <read_process_output_call>,
    arg=0x6ffff021183, handlers=handlers@entry=0x0, hfun=hfun@entry=0x10056e650 
<read_process_output_error_handler>)
    at ../../src/eval.c:1510
#33 0x000000010056eae9 in read_and_dispose_of_process_output (coding=<optimized 
out>, nbytes=3341,
    chars=<optimized out>, p=0x100acaa8b <initial_argv+3>) at 
../../src/process.c:6320
#34 read_process_output (proc=proc@entry=0x6002bac45, channel=channel@entry=7) 
at ../../src/process.c:6230
#35 0x00000001005774b2 in wait_reading_process_output 
(time_limit=time_limit@entry=0, nsecs=nsecs@entry=100000000,
    read_kbd=<optimized out>, read_kbd@entry=0, 
do_display=do_display@entry=false, wait_for_cell=<optimized out>,
    wait_for_cell@entry=0x0, wait_proc=<optimized out>, wait_proc@entry=0x0, 
just_wait_proc=<optimized out>,
    just_wait_proc@entry=0) at ../../src/process.c:5914
#36 0x0000000100402bdb in Fsleep_for (seconds=<optimized out>, 
milliseconds=<optimized out>) at ../../src/dispnew.c:6231
#37 0x000000010056b52a in exec_byte_code (fun=<optimized out>, 
fun@entry=0x60025a68d, args_template=<optimized out>,
    nargs=<optimized out>, nargs@entry=792633534417207297, args=<optimized 
out>, args@entry=0xffffc490)
    at ../../src/bytecode.c:815
#38 0x000000010052ac4e in fetch_and_exec_byte_code (args=0xffffc490, 
nargs=792633534417207297,
    args_template=<optimized out>, fun=0x60025a68d) at ../../src/eval.c:3094
#39 funcall_lambda (fun=0x60025a68d, fun@entry=0x100a457c8 <current_thread>, 
nargs=792633534417207297, nargs@entry=1,
    arg_vector=arg_vector@entry=0xffffc490) at ../../src/eval.c:3166
#40 0x000000010052f38e in apply_lambda (fun=0x100a457c8 <current_thread>, 
fun@entry=0x60025a68d, args=<optimized out>,
    count=..., count@entry=...) at ../../src/eval.c:3116
#41 0x000000010052a283 in eval_sub (form=form@entry=0x6ffff031833) at 
../../src/eval.c:2601
#42 0x00000001005301f2 in Feval (form=0x6ffff031833, lexical=<optimized out>) 
at ../../src/eval.c:2375
#43 0x000000010056b52a in exec_byte_code (fun=<optimized out>, 
fun@entry=0x6ffff80387d, args_template=<optimized out>,
    nargs=<optimized out>, nargs@entry=-4971973988617027584, args=<optimized 
out>, args@entry=0xffffc720)
    at ../../src/bytecode.c:815
#44 0x000000010052ac4e in fetch_and_exec_byte_code (args=0xffffc720, 
nargs=-4971973988617027584,
    args_template=<optimized out>, fun=0x6ffff80387d) at ../../src/eval.c:3094
#45 funcall_lambda (fun=0x6ffff80387d, fun@entry=0x100a457c8 <current_thread>, 
nargs=-4971973988617027584,
    nargs@entry=0, arg_vector=arg_vector@entry=0xffffc720) at 
../../src/eval.c:3166
#46 0x000000010052f38e in apply_lambda (fun=0x100a457c8 <current_thread>, 
fun@entry=0x6ffff80387d,
    args=<optimized out>, count=..., count@entry=...) at ../../src/eval.c:3116
#47 0x000000010052a283 in eval_sub (form=form@entry=0x6ffffc2d66b) at 
../../src/eval.c:2601
#48 0x00000001005301f2 in Feval (form=0x6ffffc2d66b, lexical=<optimized out>) 
at ../../src/eval.c:2375
#49 0x0000000100528b5b in internal_condition_case (bfun=bfun@entry=0x1004a1da0 
<top_level_2>,
    handlers=handlers@entry=0x90, hfun=hfun@entry=0x1004a80e0 <cmd_error>) at 
../../src/eval.c:1486
#50 0x00000001004a482d in top_level_1 (ignore=<optimized out>) at 
../../src/keyboard.c:1174
#51 0x0000000100528af9 in internal_catch (tag=tag@entry=0xdb00, 
func=func@entry=0x1004a47d0 <top_level_1>,
    arg=arg@entry=0x0) at ../../src/eval.c:1209
#52 0x00000001004a1cd8 in command_loop () at ../../src/keyboard.c:1134
#53 0x00000001004a7c36 in recursive_edit_1 () at ../../src/keyboard.c:744
#54 0x00000001004a7ff9 in Frecursive_edit () at ../../src/keyboard.c:827
#55 0x00000001005cf75b in main (argc=<optimized out>, argv=<optimized out>) at 
../../src/emacs.c:2625
(gdb) thread 2
[Switching to thread 2 (Thread 1000.0xe8c)]
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf9985783 in ReadFile () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x000000018012037a in wait_sig(void*) () from /usr/bin/cygwin1.dll
#3  0x0000000180044893 in cygthread::callfunc(bool) () from /usr/bin/cygwin1.dll
#4  0x0000000180044e4a in cygthread::stub(void*) () from /usr/bin/cygwin1.dll
#5  0x0000000180045863 in _cygtls::call2(unsigned int (*)(void*, void*), void*, 
void*) () from /usr/bin/cygwin1.dll
#6  0x0000000180045914 in _cygtls::call(unsigned int (*)(void*, void*), void*) 
() from /usr/bin/cygwin1.dll
#7  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#8  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#9  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) thread 3
[Switching to thread 3 (Thread 1000.0x1248)]
#0  0x00007ffbfbfad734 in ntdll!ZwFsControlFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfad734 in ntdll!ZwFsControlFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf99c8166 in KERNELBASE!ConnectNamedPipe () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x00000001800a282e in fhandler_pty_master::pty_master_thread() () from 
/usr/bin/cygwin1.dll
#3  0x0000000180044893 in cygthread::callfunc(bool) () from /usr/bin/cygwin1.dll
#4  0x0000000180044e4a in cygthread::stub(void*) () from /usr/bin/cygwin1.dll
#5  0x0000000180045863 in _cygtls::call2(unsigned int (*)(void*, void*), void*, 
void*) () from /usr/bin/cygwin1.dll
#6  0x0000000180045914 in _cygtls::call(unsigned int (*)(void*, void*), void*) 
() from /usr/bin/cygwin1.dll
#7  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#8  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#9  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) thread 4
[Switching to thread 4 (Thread 1000.0x1594)]
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf9985783 in ReadFile () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x00000001800a41f3 in fhandler_pty_master::pty_master_fwd_thread() () from 
/usr/bin/cygwin1.dll
#3  0x0000000180044893 in cygthread::callfunc(bool) () from /usr/bin/cygwin1.dll
#4  0x0000000180044e4a in cygthread::stub(void*) () from /usr/bin/cygwin1.dll
#5  0x0000000180045863 in _cygtls::call2(unsigned int (*)(void*, void*), void*, 
void*) () from /usr/bin/cygwin1.dll
#6  0x0000000180045914 in _cygtls::call(unsigned int (*)(void*, void*), void*) 
() from /usr/bin/cygwin1.dll
#7  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#8  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#9  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) thread 5
[Switching to thread 5 (Thread 1000.0x84c)]
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf9985783 in ReadFile () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x00000001800ebb04 in proc_waiter(void*) () from /usr/bin/cygwin1.dll
#3  0x0000000180044893 in cygthread::callfunc(bool) () from /usr/bin/cygwin1.dll
#4  0x0000000180044e4a in cygthread::stub(void*) () from /usr/bin/cygwin1.dll
#5  0x0000000180045863 in _cygtls::call2(unsigned int (*)(void*, void*), void*, 
void*) () from /usr/bin/cygwin1.dll
#6  0x0000000180045914 in _cygtls::call(unsigned int (*)(void*, void*), void*) 
() from /usr/bin/cygwin1.dll
#7  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#8  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#9  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) thread 6
[Switching to thread 6 (Thread 1000.0x8e8)]
#0  0x00007ffbfbfad094 in ntdll!ZwWaitForSingleObject () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfad094 in ntdll!ZwWaitForSingleObject () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf99730ce in WaitForSingleObjectEx () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x0000000180044e81 in cygthread::stub(void*) () from /usr/bin/cygwin1.dll
#3  0x0000000180045863 in _cygtls::call2(unsigned int (*)(void*, void*), void*, 
void*) () from /usr/bin/cygwin1.dll
#4  0x0000000180045914 in _cygtls::call(unsigned int (*)(void*, void*), void*) 
() from /usr/bin/cygwin1.dll
#5  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#6  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#7  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) thread 7
[Switching to thread 7 (Thread 1000.0xd98)]
#0  0x00007ffbfbfad094 in ntdll!ZwWaitForSingleObject () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfad094 in ntdll!ZwWaitForSingleObject () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf99730ce in WaitForSingleObjectEx () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x0000000180044e81 in cygthread::stub(void*) () from /usr/bin/cygwin1.dll
#3  0x0000000180045863 in _cygtls::call2(unsigned int (*)(void*, void*), void*, 
void*) () from /usr/bin/cygwin1.dll
#4  0x0000000180045914 in _cygtls::call(unsigned int (*)(void*, void*), void*) 
() from /usr/bin/cygwin1.dll
#5  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#6  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#7  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) thread 8
[Switching to thread 8 (Thread 1000.0x16e4)]
#0  0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbfbfdcbee in ntdll!DbgUiRemoteBreakin () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#2  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#3  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#4  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)


Stack traces in emacsclient.exe:

Attaching to program `/home/bruno/emacs/build-cygwin64/lib-src/emacsclient', 
process 1524
[New Thread 1524.0x14fc]
[New Thread 1524.0xaa8]
[New Thread 1524.0x16e0]
0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) info threads
  Id   Target Id         Frame
* 3    Thread 1524.0x16e0 0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  2    Thread 1524.0xaa8 0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
  1    Thread 1524.0x14fc 0x00007ffbfbfadb64 in ntdll!ZwWaitForMultipleObjects 
()
   from /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) thread 1
[Switching to thread 1 (Thread 1524.0x14fc)]
#0  0x00007ffbfbfadb64 in ntdll!ZwWaitForMultipleObjects () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfadb64 in ntdll!ZwWaitForMultipleObjects () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf99a1be0 in WaitForMultipleObjectsEx () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x0000000180093f5c in fhandler_socket::wait_for_events(long, unsigned int) 
[clone .part.51] ()
   from /usr/bin/cygwin1.dll
#3  0x0000000180094443 in fhandler_socket::recvfrom(void*, unsigned long, int, 
sockaddr*, int*) ()
   from /usr/bin/cygwin1.dll
#4  0x00000001800d0293 in cygwin_recv () from /usr/bin/cygwin1.dll
#5  0x00000001801197eb in _sigfe () from /usr/bin/cygwin1.dll
#6  0x00000001004034da in main (argc=4, argv=0xffffcc40) at 
../../lib-src/emacsclient.c:2161
(gdb) thread 2
[Switching to thread 2 (Thread 1524.0xaa8)]
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfad0d4 in ntdll!ZwReadFile () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbf9985783 in ReadFile () from 
/cygdrive/c/WINDOWS/System32/KERNELBASE.dll
#2  0x000000018012037a in wait_sig(void*) () from /usr/bin/cygwin1.dll
#3  0x0000000180044893 in cygthread::callfunc(bool) () from /usr/bin/cygwin1.dll
#4  0x0000000180044e4a in cygthread::stub(void*) () from /usr/bin/cygwin1.dll
#5  0x0000000180045863 in _cygtls::call2(unsigned int (*)(void*, void*), void*, 
void*) () from /usr/bin/cygwin1.dll
#6  0x0000000180045914 in _cygtls::call(unsigned int (*)(void*, void*), void*) 
() from /usr/bin/cygwin1.dll
#7  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#8  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#9  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) thread 3
[Switching to thread 3 (Thread 1524.0x16e0)]
#0  0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
(gdb) where
#0  0x00007ffbfbfb0b41 in ntdll!DbgBreakPoint () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#1  0x00007ffbfbfdcbee in ntdll!DbgUiRemoteBreakin () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#2  0x00007ffbfa6a7614 in KERNEL32!BaseThreadInitThunk () from 
/cygdrive/c/WINDOWS/System32/KERNEL32.DLL
#3  0x00007ffbfbf626b1 in ntdll!RtlUserThreadStart () from 
/cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll
#4  0x0000000000000000 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)