From mboxrd@z Thu Jan  1 00:00:00 1970
From: Randolph Chung <randolph@tausq.org>
Subject: Re: [PATCH] parisc: fix kernel crash when unwinding a userspace process
Date: Fri, 21 Nov 2008 18:11:49 +0800
Message-ID: <49268965.7010401@tausq.org>
References: <200811202258.56561.deller@gmx.de>
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Cc: linux-parisc@vger.kernel.org,
	Kyle Mc Martin <kyle@hera.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
To: Helge Deller <deller@gmx.de>
Return-path: <linux-parisc-owner@vger.kernel.org>
In-Reply-To: <200811202258.56561.deller@gmx.de>
List-ID: <linux-parisc.vger.kernel.org>
List-Id: linux-parisc.vger.kernel.org

Helge Deller wrote:
> Any user on existing parisc 32- and 64bit-kernels can easily crash
> the kernel and as such enforce a DSO.
> A simple testcase is available here: 
> 	http://gsyprf10.external.hp.com/~deller/crash.tgz
> 
> The problem is introduced by the fact, that the handle_interruption()
> crash handler calls the show_regs() function, which in turn tries
> to unwind the stack by calling parisc_show_stack().
> Since the stack contains userspace addresses, a try to unwind 
> the stack is dangerous and useless and leads to the crash.

Helge,

I think this is ok, but can you preserve the printing of IAOQ/RP even 
for user processes?

randolph