examining Linux core file?

[Konstantin Belousov]

On Mon, Jan 15, 2018 at 10:02:58PM -0500, Pedro Giffuni wrote:
> > On Sun, Jan 14, 2018 at 7:31 PM, Benjamin Kaduk <kaduk at mit.edu> wrote:
> > > On Sun, Jan 14, 2018 at 07:57:01AM -0800, Chuck Tuffli wrote:
> > >> If a Linux application running under the Linux emulation  (a.k.a.
> > >> Linuxulator) core dumps, is it possible to examine the resulting core
> > >> file? lldb didn't seem to like it:
> > >
> > > I wonder how a Linux gdb running under the Linuxulator would fare
> > > with it?
> >
> > Sorry, that's what I was trying to show with the last example. The
> > Linux gdb from CentOS running under the Linuxulator gives:
> >
> > # gdb -q ./testcases/bin/mremap05 mremap05.core
> > Reading symbols from /opt/ltp/testcases/bin/mremap05...done.
> >
> > warning: A handler for the OS ABI "FreeBSD ELF" is not built into this
> > configuration
> > of GDB.  Attempting to continue with the default i386:x86-64 settings.
> >
> > "/opt/ltp/mremap05.core": no core file handler recognizes format
> 
> Weird, I think you would need to build a cross-gdb.
> 
> My memory is sketchy but you may need to build a complete 
> cross-toolchain for that. Long-long ago we actually did that but the 
> resulting linux binaries were weird and needed branding always.

No cross-toolchain will help there.  Problem is that the binary is Linux,
while core is FreeBSD.  There are enough details significant to the debugger
that make such combination a new platform.