From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751482AbXFZHys (ORCPT ); Tue, 26 Jun 2007 03:54:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751348AbXFZHyj (ORCPT ); Tue, 26 Jun 2007 03:54:39 -0400 Received: from wa-out-1112.google.com ([209.85.146.181]:58451 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751271AbXFZHyh (ORCPT ); Tue, 26 Jun 2007 03:54:37 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=kZX3ld5nIZGyB3VG94qrnMqX2n++nJJYzeh5mMxRMSeYnqcXj3Jso9CFqXzd3DwiYdScED7or4GP8XXjtNCN8PBu7+N2Q9+Zv3xMiWBuChVEElikhAffZnghNk065isL/buqO3rTpScrCmCun6nWDb6FsX23/t3D19GDkMtkaqY= Message-ID: <863e9df20706260054p664635beme3081da113844c2@mail.gmail.com> Date: Tue, 26 Jun 2007 13:24:36 +0530 From: "Abhishek Sagar" To: michael@ellerman.id.au Subject: Re: [PATCH 3/3] Make jprobes a little safer for users 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 In-Reply-To: <1182839683.6673.22.camel@concordia.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <78935473b1f70c863ab0be7d6cf4bcb04922b20b.1182822366.git.michael@ellerman.id.au> <7a070581b2fe53ea65216e86c86abc4f40464341.1182822366.git.michael@ellerman.id.au> <863e9df20706252319j239eaf44wee7a46ad742c9585@mail.gmail.com> <1182839683.6673.22.camel@concordia.ozlabs.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 6/26/07, Michael Ellerman wrote: > It did occur to me that someone might be doing something crazy like > branching to code that's not in the kernel/module text - but I was > hoping that wouldn't be the case. I'm not sure what ITCM is? The reference to tightly coupled memory (ITCM) was just to have you consider the possibility of the jprobe handler being outside kernel text region. Totally paranoid really. > > > int __kprobes register_jprobe(struct jprobe *jp) > > > { > > > + unsigned long addr = arch_deref_entry_point(jp->entry); > > > + > > > + if (!kernel_text_address(addr)) > > > + return -EINVAL; > > > > Seems like you're checking for the jprobe handler to be within > > kernel/module range. Why not narrow this down to just module range > > (!module_text_address(addr), say)? Core kernel functions would not be > > ending with a 'jprobe_return()' anyway. > > There's jprobe code in net/ipv4/tcp_probe.c and net/dccp/probe.c that > can be builtin or modular, so I think kernel_text_address() is right. Ok..thanks for that clarification. -- Abhishek Sagar - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/