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From: hpa@zytor.com (H. Peter Anvin)
To: linux-kernel@vger.kernel.org
Subject: Re: __init poisoning for i386, too
Date: Thu, 7 Oct 2004 21:05:45 +0000 (UTC)	[thread overview]
Message-ID: <ck4b39$fmp$1@terminus.zytor.com> (raw)
In-Reply-To: <20041007061610.GU9106@holomorphy.com>

Followup to:  <20041007061610.GU9106@holomorphy.com>
By author:    William Lee Irwin III <wli@holomorphy.com>
In newsgroup: linux.dev.kernel
>
> On Thu, Oct 07, 2004 at 12:18:55AM +0200, Pavel Machek wrote:
> > Overwrite __init section so calls to __init functions from normal code
> > are catched, reliably. I wonder if this should be configurable... but
> > it is configurable on x86-64 so I copied it. Please apply,
> 
> Any chance we could:
> (a) set the stuff to 0x0f0b so illegal instructions come of it; jumps are
> 	most often aligned to something > 16 bits anyway
> (b) poison __initdata, memsetting to some bit pattern oopsable to dereference
> 

What's wrong with using 0xCC (breakpoint instruction)?

If you want an illegal instruction, 0xFF 0xFF is an illegal
instruction, so filling memory with 0xFF will do what you want.

	-hpa

  reply	other threads:[~2004-10-07 21:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-06 22:18 Pavel Machek
2004-10-06 22:29 ` Andrew Morton
2004-10-07  8:22   ` Geert Uytterhoeven
2004-10-06 23:56 ` Nigel Cunningham
2004-10-07  8:02   ` Pavel Machek
2004-10-07  6:16 ` William Lee Irwin III
2004-10-07 21:05   ` H. Peter Anvin [this message]
2004-10-08 11:08     ` William Lee Irwin III
2004-10-08 11:23       ` Ryan Cumming
     [not found] <20041006221854.GA1622@elf.ucw.cz.suse.lists.linux.kernel>
     [not found] ` <20041007061610.GU9106@holomorphy.com.suse.lists.linux.kernel>
2004-10-07 11:28   ` Andi Kleen

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