Re: Variable locations in a loaded kernel (bsd.gdb)

[Andrew Cagney <ac131313 at cygnus dot com>]

> Gidday there,
> 
> 	I'm trying to find how a specific variable is referenced in an
> OpenBSD 2.8 kernel.  I build a kernel with symbols, and load it into gdb,
> however I can't find a way to see where a specific variable is stored
> (stack, memory, register etc...).  I can't run the kernel, and when I type
> 'p function::variable' it responds with...
> 
> No frame is currently executing in block scpshc_decompress.
> 
> 	Once I have the offset, or address or whatever about the variable,
> then I can examine its value in 'ddb' after the kernel crashes.
> 
> 	Thanks in advance.  I'm running GDB 4.16.1.  The 'configure'
> script doesn't let me compile version 5 on OBSD2.8.

Outch! They are both really old GDBs. Could I sugest downloading 
someting more recent? The snapshots are tracking the unreleased 5.1 branch:

	http://sources.redhat.com/gdb/download

Hopefully that at least builds (Changes to get GDB working on the 
various BSD OSs were only committed after GDB 5 was released).

Having done this, I would add a note of caution.  4.16.1 as a GDB 
version number makes me suspicious - afaik it doesn't exist!  I suspect 
it is in fact 4.16ob1 - an OpenBSD specific branch of GDB - and may 
contain features never contributed to the FSF.

	Andrew