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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Roland McGrath <roland@redhat.com>
Cc: David Woodhouse <dwmw2@redhat.com>,
	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	Paul Mackerras <paulus@samba.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 1/2] powerpc: ptrace CHECK_FULL_REGS
Date: Tue, 25 Sep 2007 13:58:46 +1000	[thread overview]
Message-ID: <1190692726.31978.0.camel@localhost.localdomain> (raw)
In-Reply-To: <20070925005945.02E924D04B7@magilla.localdomain>


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.

      reply	other threads:[~2007-09-25  3:58 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-24 23:50 [PATCH 1/2] powerpc: ptrace CHECK_FULL_REGS Roland McGrath
2007-09-25  0:33 ` Benjamin Herrenschmidt
2007-09-25  0:59   ` Roland McGrath
2007-09-25  3:58     ` Benjamin Herrenschmidt [this message]

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