From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752308Ab3HZS3h (ORCPT ); Mon, 26 Aug 2013 14:29:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3071 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752210Ab3HZS3g (ORCPT ); Mon, 26 Aug 2013 14:29:36 -0400 Date: Mon, 26 Aug 2013 14:29:07 -0400 From: Dave Jones To: Steven Rostedt Cc: paulmck@linux.vnet.ibm.com, Linux Kernel Subject: Re: suspicious RCU usage (perf) Message-ID: <20130826182907.GB25202@redhat.com> Mail-Followup-To: Dave Jones , Steven Rostedt , paulmck@linux.vnet.ibm.com, Linux Kernel References: <20130826145838.GA8377@redhat.com> <20130826162928.GQ3871@linux.vnet.ibm.com> <20130826133041.3d750b1b@gandalf.local.home> <20130826175012.GA25202@redhat.com> <20130826141814.54dcaa89@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130826141814.54dcaa89@gandalf.local.home> 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 Mon, Aug 26, 2013 at 02:18:14PM -0400, Steven Rostedt wrote: > On Mon, 26 Aug 2013 13:50:12 -0400 > Dave Jones wrote: > > > > This was triggered as a regular user fwiw. > > I had not been running perf, or any other tracing. It was just left > > fuzzing over the weekend with no interaction at all. > > So you are telling me that ftrace was enabled by a regular user? If so, > that's a huge issue. quite. > So my question to you. If you were not running perf or any other > tracing, and this is all just non-root user. How the hell did perf > function tracing get started on your box???? What mechanisms are available that would trigger it being enabled ? Is there some path through sys_perf_open_event that might be missing a capability check perhaps ? Dave