From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759816Ab3FCWVx (ORCPT ); Mon, 3 Jun 2013 18:21:53 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:32917 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758814Ab3FCWMB (ORCPT ); Mon, 3 Jun 2013 18:12:01 -0400 X-Authority-Analysis: v=2.0 cv=fZsvOjsF c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=Ciwy3NGCPMMA:10 a=WpD12FY-48YA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=N1bbi4PdpE4A:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=5RAGcMhyOaGCbW0FJhMA:9 a=Zh68SRI7RUMA:10 a=jEp0ucaQiEUA:10 a=9J5VuaLb3qoA:10 a=jeBq3FmKZ4MA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-Id: <20130603221154.654385631@goodmis.org> User-Agent: quilt/0.60-1 Date: Mon, 03 Jun 2013 18:10:31 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Prarit Bhargava , Mike Galbraith , Thomas Gleixner Subject: [15/65] tick: Cleanup NOHZ per cpu data on cpu down References: <20130603221016.243553628@goodmis.org> Content-Disposition: inline; filename=0015-tick-Cleanup-NOHZ-per-cpu-data-on-cpu-down.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.6.11.5 stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner [ Upstream commit 4b0c0f294f60abcdd20994a8341a95c8ac5eeb96 ] Prarit reported a crash on CPU offline/online. The reason is that on CPU down the NOHZ related per cpu data of the dead cpu is not cleaned up. If at cpu online an interrupt happens before the per cpu tick device is registered the irq_enter() check potentially sees stale data and dereferences a NULL pointer. Cleanup the data after the cpu is dead. Reported-by: Prarit Bhargava Cc: stable@vger.kernel.org Cc: Mike Galbraith Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1305031451561.2886@ionos Signed-off-by: Thomas Gleixner Signed-off-by: Steven Rostedt --- kernel/time/tick-sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index e430b97..7dba89d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -909,7 +909,7 @@ void tick_cancel_sched_timer(int cpu) hrtimer_cancel(&ts->sched_timer); # endif - ts->nohz_mode = NOHZ_MODE_INACTIVE; + memset(ts, 0, sizeof(*ts)); } #endif -- 1.7.10.4