From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754631AbXFZCCQ (ORCPT ); Mon, 25 Jun 2007 22:02:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752277AbXFZCCF (ORCPT ); Mon, 25 Jun 2007 22:02:05 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:55423 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752085AbXFZCCE (ORCPT ); Mon, 25 Jun 2007 22:02:04 -0400 Date: Mon, 25 Jun 2007 19:00:57 -0700 From: Andrew Morton To: Michael Ellerman Cc: , , , , Christoph Hellwig , , Subject: Re: [PATCH 3/3] Make jprobes a little safer for users Message-Id: <20070625190057.c8dcb110.akpm@linux-foundation.org> In-Reply-To: <7a070581b2fe53ea65216e86c86abc4f40464341.1182822366.git.michael@ellerman.id.au> References: <78935473b1f70c863ab0be7d6cf4bcb04922b20b.1182822366.git.michael@ellerman.id.au> <7a070581b2fe53ea65216e86c86abc4f40464341.1182822366.git.michael@ellerman.id.au> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Jun 2007 11:48:51 +1000 (EST) 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. > > Signed-off-by: Michael Ellerman > --- > arch/ia64/kernel/kprobes.c | 7 ++++++- > arch/powerpc/kernel/kprobes.c | 11 ++++++++--- > kernel/kprobes.c | 9 +++++++++ We're missing a declaration of arch_deref_entry_point() in some header file?