From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751634Ab3EEJFK (ORCPT ); Sun, 5 May 2013 05:05:10 -0400 Received: from mail-ea0-f182.google.com ([209.85.215.182]:49453 "EHLO mail-ea0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751525Ab3EEJFI (ORCPT ); Sun, 5 May 2013 05:05:08 -0400 Date: Sun, 5 May 2013 11:05:04 +0200 From: Ingo Molnar To: Borislav Petkov Cc: a.p.zijlstra@chello.nl, hpa@zytor.com, linux-kernel@vger.kernel.org, stable@kernel.org, ak@linux.intel.com, tglx@linutronix.de, linux-tip-commits@vger.kernel.org Subject: Re: [tip:perf/urgent] perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL Message-ID: <20130505090504.GB22239@gmail.com> References: <20130503121256.230745028@chello.nl> <20130504111907.GA3411@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130504111907.GA3411@pd.tnic> 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 * Borislav Petkov wrote: > On Sat, May 04, 2013 at 01:22:57AM -0700, tip-bot for Peter Zijlstra wrote: > > Commit-ID: 0f5c78b5f33ce940034743e5f9485fc81ad75b0f > > Gitweb: http://git.kernel.org/tip/0f5c78b5f33ce940034743e5f9485fc81ad75b0f > > Author: Peter Zijlstra > > AuthorDate: Fri, 3 May 2013 14:11:25 +0200 > > Committer: Ingo Molnar > > CommitDate: Sat, 4 May 2013 08:37:48 +0200 > > > > perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL > > > > We should always have proper privileges when requesting kernel > > data. > > > > Signed-off-by: Peter Zijlstra > > Cc: > > Cc: Andi Kleen > > Cc: eranian@google.com > > Link: http://lkml.kernel.org/r/20130503121256.230745028@chello.nl > > Signed-off-by: Ingo Molnar > > Link: http://lkml.kernel.org/n/tip-v0x9ky3ahzr6nm3c6ilwrili@git.kernel.org > > --- > > arch/x86/kernel/cpu/perf_event_intel_lbr.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c > > index de341d4..0e92871 100644 > > --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c > > +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c > > @@ -318,8 +318,11 @@ static void intel_pmu_setup_sw_lbr_filter(struct perf_event *event) > > if (br_type & PERF_SAMPLE_BRANCH_USER) > > mask |= X86_BR_USER; > > > > - if (br_type & PERF_SAMPLE_BRANCH_KERNEL) > > + if (br_type & PERF_SAMPLE_BRANCH_KERNEL) { > > + if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) > > + return -EACCES; > > It is probably not too late to amend this patch and remove the "-EACCES": > > arch/x86/kernel/cpu/perf_event_intel_lbr.c: In function ???intel_pmu_setup_sw_lbr_filter???: > arch/x86/kernel/cpu/perf_event_intel_lbr.c:323:4: warning: ???return??? with a value, in function returning void [enabled by default] Well, the better fix is to propagate that error condition down instead of ignoring it. Since it was the head commit for a tree others don't typically pull and base development work off I amended it. Thanks, Ingo