Re: dumper does not produce core that gdb recognizes?

[Ken Brown <kbrown@cornell.edu>]

On 7/8/2022 6:06 PM, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via Cygwin wrote:
> Hi all,
> 
> I need to do some deep debugging on Cygwin so I need to produce a core...  And it does not work.
> 
> So I reduced the problem to this minimal test case:
> 
> $ cat a.c
> #include <stdlib.h>
> 
> int main()
> {
>      abort();
> }
> 
> $ gcc -Wall -g a.c
> 
> $ echo $CYGWIN
> error_start=c:\cygwin64\bin\dumper.exe
> 
> $ ulimit -a
> core file size          (blocks, -c) unlimited
> data seg size           (kbytes, -d) unlimited
> file size               (blocks, -f) unlimited
> open files                      (-n) 3200
> pipe size            (512 bytes, -p) 8
> stack size              (kbytes, -s) 2036
> cpu time               (seconds, -t) unlimited
> max user processes              (-u) 256
> virtual memory          (kbytes, -v) unlimited
> 
> $ ./a
> *** starting debugger for pid 19934, tid 9332
> 
> $ ls -l a.*
> -rw-r--r-- 1 ANTON None      49 Jul  8 17:40 a.c
> -rwxr-xr-x 1 ANTON None  161487 Jul  8 17:41 a.exe*
> -rw-r--r-- 1 ANTON None 3331640 Jul  8 17:46 a.exe.core
> 
> $ file a.*
> a.c:        C source, ASCII text
> a.exe:      PE32+ executable (console) x86-64, for MS Windows
> a.exe.core: ELF 64-bit LSB core file, x86-64, version 1 (SYSV)
> 
> BUT: gdb does not want this core file:
> 
> $ gdb ./a.exe a.exe.core
> GNU gdb (GDB) (Cygwin 9.2-1) 9.2
> Copyright (C) 2020 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 "x86_64-pc-cygwin".
> Type "show configuration" for configuration details.
> For bug reporting instructions, please see:
> <http://www.gnu.org/software/gdb/bugs/>.
> Find the GDB manual and other documentation resources online at:
>      <http://www.gnu.org/software/gdb/documentation/>.
> 
> For help, type "help".
> Type "apropos word" to search for commands related to "word"...
> Reading symbols from ./a.exe...
> "/home/ANTON/a.exe.core": no core file handler recognizes format
> (gdb)
> 
> What I am doing wrong?

Try using a more recent gdb.  I just tried your test case with gdb-12.1-1 
(available as a test release), and it seemed to work.

Ken