Re: gdb crashes in Cygwin

["Paul Pluzhnikov" <ppluzhnikov at google dot com>]

On Sun, Oct 12, 2008 at 6:41 AM, Mike Ady <mike.ady2@gmail.com> wrote:
> Hi,
>
> I apologize for posting to this forum.  I tried the Cygwin forum, and
> I got no response.
>
> I am attempting to help the author of the giac/xcas program to solve
> some problems that occur only on Cygwin.  According to the author,
> "Giac/Xcas is a free computer algebra system for Windows, Mac OS X and
> Linux/Unix."  The author works primarily on Linux, and I use his
> program on Windows/Cygwin, hence the need for my help.
>
> The program, running on its own, doesn't crash.  However, when I try
> to run the program from gdb, gdb crashes.
>
> I have read the part of the gdb manual dealing with bug reports, and I
> have read "http://www.gnu.org/software/gdb/bugs/"; but I can't yet
> fulfill all of the requirements for submitting a bug report.  Can
> anyone provide some advice on how to proceed?

Use GDB to debug GDB:

  gdb -ex 'set prompt (top) ' --args gdb dumper.exe
  (top) run
  (gdb) run
  # at this point, inferior gdb should crash, and you should
  # see (top) prompt
  (top) where

> The crash is repeatable.  It occurs while the program is initializing
> but after main is called, and I am able to set a breakpoint at the
> last statement executed by the program before the crash.  (It's a
> simple call to "gettimeofday".)  A half dozen steps later (into the
> Cygwin DLL), gdb crashes.
>
> I have configured the Cygwin core dump routine "dumper.exe" to get a
> crash dump.  The dump is over 50 megabytes.  (Indeed, the program
> itself is over 50 megabytes.)  I have even tried to use gdb to analyze
> the crash dump, but gdb crashes doing that too, (with the command line
> "gdb /usr/bin/gdb.exe gdb.exe.core").

That sounds like a separate bug.
You may try the "double GDB" trick here as well:

  gdb -ex 'set prompt (top) ' --args gdb gdb gdb.exe.core
  (top) run

>
> I have downloaded the latest version of the gdb sources and I have
> built it.  It exhibits all of the same behavior:
>
> $ /usr/local/bin/gdb
> GNU gdb (GDB) 6.8.50.20081012-cvs
> ...
> This GDB was configured as "i686-pc-cygwin".
>
> Here is my environment information (I'm running Cygwin on Windows XP SP3):
>
> $ uname -a
> CYGWIN_NT-5.1 WHISTLER 1.5.25(0.156/4/2) 2008-06-12 19:34 i686 Cygwin
>
> $ gcc -v
> Reading specs from /usr/lib/gcc/i686-pc-cygwin/3.4.4/specs
> Configured with:
> /usr/build/package/orig/test.respin/gcc-3.4.4-3/configure --verbose
> --prefix=/usr --exec-prefix=/usr --sysconfd
> ir=/etc --libdir=/usr/lib --libexecdir=/usr/lib
> --mandir=/usr/share/man --infodir=/usr/share/info
> --enable-languages=c,ada,c++,d
> ,f77,pascal,java,objc --enable-nls --without-included-gettext
> --enable-version-specific-runtime-libs --without-x --enable-libgcj
>  --disable-java-awt --with-system-zlib --enable-interpreter
> --disable-libgcj-debug --enable-threads=posix --enable-java-gc=boehm
>  --disable-win32-registry --enable-sjlj-exceptions
> --enable-hash-synchronization --enable-libstdcxx-debug
> Thread model: posix
> gcc version 3.4.4 (cygming special, gdc 0.12, using dmd 0.125)
>
> $ gdb
> GNU gdb 6.8.0.20080328-cvs (cygwin-special)
> ...
> This GDB was configured as "i686-pc-cygwin".
>
> Is there anything else that I can/should do to tie this down a little better?

You could also supply dumper.exe.bz2 somewhere publicaly accessible,
and/or supply instructions on how to build it.

Cheers,
-- 
Paul Pluzhnikov