Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755348Ab3EQIoS (ORCPT ); Fri, 17 May 2013 04:44:18 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:56919 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755138Ab3EQIoQ (ORCPT ); Fri, 17 May 2013 04:44:16 -0400 Message-ID: <1368780244.2813.14.camel@ThinkPad-T5421> Subject: [RFC PATCH nohz] return NOTIFY_BAD in cpu down call back to stop offlining the cpu From: Li Zhong To: LKML Cc: Frederic Weisbecker Date: Fri, 17 May 2013 16:44:04 +0800 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13051708-0260-0000-0000-00000303F1C2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1264 Lines: 35 In tick_nohz_cpu_down_callback() if the cpu is the one handling timekeeping , it seems that we should return something that could stop notify CPU_DOWN_PREPARE, and then start notify CPU_DOWN_FAILED on the already called notifier call backs. -EINVAL will be converted to 0 by notifier_to_errno(), then the cpu would be taken down with part of the DOWN_PREPARE notifier callbacks called, and something bad could happen after that. Signed-off-by: Li Zhong --- kernel/time/tick-sched.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index bc67d42..17b8155 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -306,7 +306,7 @@ static int __cpuinit tick_nohz_cpu_down_callback(struct notifier_block *nfb, * we can't safely shutdown that CPU. */ if (have_nohz_full_mask && tick_do_timer_cpu == cpu) - return -EINVAL; + return NOTIFY_BAD; break; } return NOTIFY_OK; -- 1.7.1 -- 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/