From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755608AbaCNUUB (ORCPT ); Fri, 14 Mar 2014 16:20:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32159 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755052AbaCNUUA (ORCPT ); Fri, 14 Mar 2014 16:20:00 -0400 Date: Fri, 14 Mar 2014 16:19:43 -0400 From: Dave Jones To: Linus Torvalds Cc: Kees Cook , Sasha Levin , Linux Kernel Mailing List , a.p.zijlstra@chello.nl Subject: perf top breakage. Message-ID: <20140314201943.GB6633@redhat.com> Mail-Followup-To: Dave Jones , Linus Torvalds , Kees Cook , Sasha Levin , Linux Kernel Mailing List , a.p.zijlstra@chello.nl MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 12:41:41PM -0700, Linus Torvalds wrote: > On Fri, Mar 14, 2014 at 12:32 PM, Linus Torvalds > wrote: > > > > Hmm. Do you have CONFIG_KALLSYMS enabled? > > Just to clarify. KALLSYMS is required to figure out the symbol > addresses on a kaslr system. There's no way to look them up in a > System.map file or the object file, since the addresses aren't going > to match. > > Your symptoms really sound like you might not have KALLSYMS enabled. > > I wonder if we have a "select KALLSYMS" as part of RANDOMIZE_BASE, > since you need it for debug messages too (random hex numbers aren't > too useful ;) Ok, I've figured out the cause. kaslr is a red herring. This works : # su - root $ tools/perf/perf top This doesn't: # sudo tools/perf/perf top Neither does: # su - root $ sudo tools/perf/perf top So somehow sudo+perf broke. fun. The 3.13 binary works regardless of how I call it. Dave