Re: [RFC] [PATCH] In-kernel gdbstub based on utrace Infrastructure.

From: Srikar Dronamraju
Date: Mon Nov 30 2009 - 09:05:27 EST


> >
> > I guess Christoph, Roland and Frank would be able to explain in a better
> > fashion the rational and advantages of this stub over convential gdb.
>
> Hmm,. wouldn't it make much more sense to extend the current kgdb stub
> to include userspace debugging, providing an all-in-one solution?

I see two limitations but I guess there could be ways to get over it.
1. gdb requiring file that needs to be debugged. I always
thought it can either be a user program or a vmlinux file. gdb makes
most of the information(i.e registers) from the remote protocol to
display the backtrace, variable values and the like by reading this
file.

2. Also I am not sure if gdb has a way to tell the remote to switch the
context and provide information(registers) pertaining to the user mode/
kernel mode.

There could be other limitations too that I may not be aware.
>
> I think it would be much more powerful to be able to observe the full
> software stack and not be limited by this user<->kernel barrier.
>
> (Provided the user has sufficient privileges of course).

In this implementation, the current user can debug his/her own
processes. May be if we can debug both the context from same gdb then we
might have to place restrictions..

--
Thanks and Regards
Srikar
>
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