From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755643AbaCNTIi (ORCPT ); Fri, 14 Mar 2014 15:08:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35122 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754523AbaCNTIg (ORCPT ); Fri, 14 Mar 2014 15:08:36 -0400 Date: Fri, 14 Mar 2014 15:08:24 -0400 From: Dave Jones To: Kees Cook Cc: Linus Torvalds , Sasha Levin , Linux Kernel Mailing List Subject: Re: [RFC] improve_stack: make stack dump output useful again Message-ID: <20140314190824.GA6426@redhat.com> Mail-Followup-To: Dave Jones , Kees Cook , Linus Torvalds , Sasha Levin , Linux Kernel Mailing List References: <1393114777-21588-1-git-send-email-sasha.levin@oracle.com> <5321CBDA.1060705@oracle.com> <20140313231227.GA32178@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 14, 2014 at 11:31:11AM -0700, Kees Cook wrote: > On Thu, Mar 13, 2014 at 4:12 PM, Dave Jones wrote: > > On Thu, Mar 13, 2014 at 03:03:41PM -0700, Linus Torvalds wrote: > > > > > You need to look at the *symbol* number. In this output: > > > > > > [] do_one_initcall+0xc2/0x1e0 > > > > > > that "ffffffff810020c2" is crap, and is going away. The address that > > > is meaningful and valid is the "do_one_initcall+0xc2" part. > > > > > > *That* is the part you'd use to parse in user space. > > > > > > Try it today with the CONFIG_RANDOMIZE_BASE option to see. Using the > > > hex number doesn't *work*. > > > > That reminds me, perf top is still busted when this option is enabled. > > Hrm, works for me. I'm not very familiar with what to expect, but > comparing output between kaslr boot and nokaslr boot, it looks the > same to me. ok, nokalsr makes it work too. Booting with that and using the perf binary from 3.14rc6 , I just see.. 9.30% [kernel] [k] 0xffffffffaf18e887 7.98% [kernel] [k] 0xffffffffaf3276c7 6.10% [kernel] [k] 0xffffffffaf18dd3a 4.39% [kernel] [k] 0xffffffffaf327717 1.71% [kernel] [k] 0xffffffffaf18e89c 1.52% [kernel] [k] 0xffffffffaf3276cc Curiously, if I use the perf binary from 3.13, I see everything lumped together as.. 95.89% [kernel].exit.text [k] 0x000000002e586c26 (When kaslr is disabled both binaries work fine) Also maybe related: The rc6 binary claims it can't read symbols from vmlinux when kaslr is enabled. Dave