I also tried to core dump with:
/usr/bin/cygrunsrv -I sshd -d "CYGWIN sshd" -p /usr/sbin/sshd -a "-D"
-y tcpip -u cyg_server -w xxxxxx -e CYGWIN="error_start=dumper -d %1
%2"
The file is there (/sshd.exe.core), but again gdb doesn't show any
encouraging information:
$ gdb /usr/sbin/sshd.exe sshd.exe.core
GNU gdb (GDB) 7.3.50.20111026-cvs (cygwin-special)
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-cygwin".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/sbin/sshd.exe...(no debugging symbols found)...done.