From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933439AbdA0LIs (ORCPT ); Fri, 27 Jan 2017 06:08:48 -0500 Received: from mx2.suse.de ([195.135.220.15]:34738 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933639AbdA0LGD (ORCPT ); Fri, 27 Jan 2017 06:06:03 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Mark Rutland , Anna-Maria Gleixner , Richard Cochran , Sebastian Andrzej Siewior , Daniel Lezcano , Peter Zijlstra , Sebastian Frias , Thibaud Cornic , Robin Murphy , Jiri Slaby Subject: [PATCH 3.12 129/235] tick/broadcast: Prevent NULL pointer dereference Date: Fri, 27 Jan 2017 11:54:22 +0100 Message-Id: X-Mailer: git-send-email 2.11.0 In-Reply-To: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> References: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Gleixner 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit c1a9eeb938b5433947e5ea22f89baff3182e7075 upstream. When a disfunctional timer, e.g. dummy timer, is installed, the tick core tries to setup the broadcast timer. If no broadcast device is installed, the kernel crashes with a NULL pointer dereference in tick_broadcast_setup_oneshot() because the function has no sanity check. Reported-by: Mason Signed-off-by: Thomas Gleixner Cc: Mark Rutland Cc: Anna-Maria Gleixner Cc: Richard Cochran Cc: Sebastian Andrzej Siewior Cc: Daniel Lezcano Cc: Peter Zijlstra , Cc: Sebastian Frias Cc: Thibaud Cornic Cc: Robin Murphy Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr Signed-off-by: Jiri Slaby --- kernel/time/tick-broadcast.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 8a95408b1345..f27eb5db3260 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -778,6 +778,9 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { int cpu = smp_processor_id(); + if (!bc) + return; + /* Set it up only once ! */ if (bc->event_handler != tick_handle_oneshot_broadcast) { int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC; -- 2.11.0