Re: [PATCH 1/2] powerpc: ptrace CHECK_FULL_REGS

From: Benjamin Herrenschmidt
Date: Mon Sep 24 2007 - 23:59:27 EST



On Mon, 2007-09-24 at 17:59 -0700, Roland McGrath wrote:
> > Yup, I think I ditched most of them.. for some reason I decided it
> > couldn't happen, but maybe I'm wrong ?
>
> Well, it's a BUG_ON. It's supposed to be for something that "can't happen".
> That's why it's a sanity check, not a wild assertion. ;-)
>
> The 2/2 patch is an example of a bug that CHECK_FULL_REGS catches.
> In the status quo, using PTRACE_PEEKUSR in a bug case crashes while using
> PTRACE_GETREGS in the same place might get bogus data. (In the actual bug
> thus found, the data is not bogus and only the bit that FULL_REGS checks is.)

Fair enough.

Ben.


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