From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.210]:39919 "EHLO mail.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752738AbXFZFyf (ORCPT ); Tue, 26 Jun 2007 01:54:35 -0400 Date: Tue, 26 Jun 2007 07:53:47 +0200 From: Christoph Hellwig Subject: Re: [PATCH 3/3] Make jprobes a little safer for users Message-ID: <20070626055347.GB6841@lst.de> References: <78935473b1f70c863ab0be7d6cf4bcb04922b20b.1182822366.git.michael@ellerman.id.au> <7a070581b2fe53ea65216e86c86abc4f40464341.1182822366.git.michael@ellerman.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7a070581b2fe53ea65216e86c86abc4f40464341.1182822366.git.michael@ellerman.id.au> Sender: linux-arch-owner@vger.kernel.org To: Michael Ellerman Cc: linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, linux-ia64@vger.kernel.org, linux-arch@vger.kernel.org, Andrew Morton , Christoph Hellwig , anil.s.keshavamurthy@intel.com, ananth@in.ibm.com List-ID: On Tue, Jun 26, 2007 at 11:48:51AM +1000, Michael Ellerman wrote: > I realise jprobes are a razor-blades-included type of interface, but > that doesn't mean we can't try and make them safer to use. This guy I > know once wrote code like this: > > struct jprobe jp = { .kp.symbol_name = "foo", .entry = "jprobe_foo" }; > > And then his kernel exploded. Oops. > > This patch adds an arch hook, arch_deref_entry_point() (I don't like it either) > which takes the void * in a struct jprobe, and gives back the text address > that it represents. > > We can then use that in register_jprobe() to check that the entry point > we're passed is actually in the kernel text, rather than just some random > value. Please don't add more weak functions, they're utterly horrible for anyone trying to understand the code. Otherwise this looks fine to me.