Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932211Ab3IHDVE (ORCPT ); Sat, 7 Sep 2013 23:21:04 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:56232 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756778Ab3IHDSz (ORCPT ); Sat, 7 Sep 2013 23:18:55 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Vince Weaver" , "Mark Rutland" , "Russell King" , "Will Deacon" Date: Sun, 08 Sep 2013 03:52:01 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [070/121] ARM: 7809/1: perf: fix event validation for software group leaders In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.101 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1964 Lines: 52 3.2.51-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon commit c95eb3184ea1a3a2551df57190c81da695e2144b upstream. It is possible to construct an event group with a software event as a group leader and then subsequently add a hardware event to the group. This results in the event group being validated by adding all members of the group to a fake PMU and attempting to allocate each event on their respective PMU. Unfortunately, for software events wthout a corresponding arm_pmu, this results in a kernel crash attempting to dereference the ->get_event_idx function pointer. This patch fixes the problem by checking explicitly for software events and ignoring those in event validation (since they can always be scheduled). We will probably want to revisit this for 3.12, since the validation checks don't appear to work correctly when dealing with multiple hardware PMUs anyway. Reported-by: Vince Weaver Tested-by: Vince Weaver Tested-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Ben Hutchings --- arch/arm/kernel/perf_event.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -326,6 +326,9 @@ validate_event(struct pmu_hw_events *hw_ struct hw_perf_event fake_event = event->hw; struct pmu *leader_pmu = event->group_leader->pmu; + if (is_software_event(event)) + return 1; + if (event->pmu != leader_pmu || event->state < PERF_EVENT_STATE_OFF) return 1; -- 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/