dumper does not produce core that gdb recognizes?

dumper does not produce core that gdb recognizes?

[Lavrentiev, Anton (NIH/NLM/NCBI) [C]]

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?

TIA,

Anton Lavrentiev
Contractor NIH/NLM/NCBI

Re: dumper does not produce core that gdb recognizes?

[Ken Brown]

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

RE: [EXTERNAL] Re: dumper does not produce core that gdb recognizes?

[Lavrentiev, Anton (NIH/NLM/NCBI) [C]]

> 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.

Thanks for the quick response...  Though I'd rather not use test releases.

The dumper binary and gdb in my case are supposed to be consistent with each other
(installed from the set of release packages on the same day via setup)...  So I don't
really understand the discrepancy here:  are you saying that dumper can produce a core
that current gdb cannot read?  But that's bizarre!

Anton Lavrentiev
Contractor NIH/NLM/NCBI

Re: [EXTERNAL] Re: dumper does not produce core that gdb recognizes?

[Takashi Yano]

On Fri, 8 Jul 2022 23:09:27 +0000
"Lavrentiev, Anton \(NIH/NLM/NCBI\) \[C\] wrote:
> > 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.
> 
> Thanks for the quick response...  Though I'd rather not use test releases.

The latest version of gdb that is not a test version is 11.2. But
you are using 9.2.

> The dumper binary and gdb in my case are supposed to be consistent with each other
> (installed from the set of release packages on the same day via setup)...  So I don't
> really understand the discrepancy here:  are you saying that dumper can produce a core
> that current gdb cannot read?  But that's bizarre!

Even if so, the combination of latest dumper.exe (in cygwin 3.3.5
package) and gdb 11.2 do not have such a problem. Therefore, we
have nothing to do for that.

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>