From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38C94C433E0 for ; Fri, 19 Mar 2021 08:02:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEB1B64F6D for ; Fri, 19 Mar 2021 08:02:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234316AbhCSIBm (ORCPT ); Fri, 19 Mar 2021 04:01:42 -0400 Received: from mail-m118208.qiye.163.com ([115.236.118.208]:44750 "EHLO mail-m118208.qiye.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234246AbhCSIBJ (ORCPT ); Fri, 19 Mar 2021 04:01:09 -0400 Received: from vivo-HP-ProDesk-680-G4-PCI-MT.vivo.xyz (unknown [58.251.74.232]) by mail-m118208.qiye.163.com (Hmail) with ESMTPA id A6E20E034C; Fri, 19 Mar 2021 16:01:05 +0800 (CST) From: Wang Qing To: Tejun Heo , Lai Jiangshan , Andrew Morton , "Guilherme G. Piccoli" , Andrey Ignatov , Vlastimil Babka , Petr Mladek , Wang Qing , Santosh Sivaraj , linux-kernel@vger.kernel.org Subject: [PATCH V2] workqueue: watchdog: update wq_watchdog_touched for unbound lockup checking Date: Fri, 19 Mar 2021 16:00:36 +0800 Message-Id: <1616140838-24222-1-git-send-email-wangqing@vivo.com> X-Mailer: git-send-email 2.7.4 X-HM-Spam-Status: e1kfGhgUHx5ZQUtXWQgYFAkeWUFZS1VLWVdZKFlBSE83V1ktWUFJV1kPCR oVCBIfWUFZHR9DSRodH00aGU4dVkpNSk1KT0tDTU1KSkJVEwETFhoSFyQUDg9ZV1kWGg8SFR0UWU FZT0tIVUpKS0hOSFVLWQY+ X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Nyo6MCo*KD8SVk00LRM2IzUv EB0aCz5VSlVKTUpNSk9LQ01NT0pIVTMWGhIXVQwaFRwKEhUcOw0SDRRVGBQWRVlXWRILWUFZTkNV SU5KVUxPVUlISVlXWQgBWUFITkxMNwY+ X-HM-Tid: 0a78498091ee2c17kusna6e20e034c Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When touch_softlockup_watchdog() is called, only wq_watchdog_touched_cpu updated, while the unbound worker_pool running on its core uses wq_watchdog_touched to determine whether locked up. This may be mischecked. My suggestion is to update both when touch_softlockup_watchdog() is called, use wq_watchdog_touched_cpu to check bound, and use wq_watchdog_touched to check unbound worker_pool. Signed-off-by: Wang Qing --- kernel/watchdog.c | 5 +++-- kernel/workqueue.c | 17 ++++++----------- 2 files changed, 9 insertions(+), 13 deletions(-) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 7110906..107bc38 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -278,9 +278,10 @@ void touch_all_softlockup_watchdogs(void) * update as well, the only side effect might be a cycle delay for * the softlockup check. */ - for_each_cpu(cpu, &watchdog_allowed_mask) + for_each_cpu(cpu, &watchdog_allowed_mask) { per_cpu(watchdog_touch_ts, cpu) = SOFTLOCKUP_RESET; - wq_watchdog_touch(-1); + wq_watchdog_touch(cpu); + } } void touch_softlockup_watchdog_sync(void) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 0d150da..be08295 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5787,22 +5787,17 @@ static void wq_watchdog_timer_fn(struct timer_list *unused) continue; /* get the latest of pool and touched timestamps */ + if (pool->cpu >= 0) + touched = READ_ONCE(per_cpu(wq_watchdog_touched_cpu, pool->cpu)); + else + touched = READ_ONCE(wq_watchdog_touched); pool_ts = READ_ONCE(pool->watchdog_ts); - touched = READ_ONCE(wq_watchdog_touched); if (time_after(pool_ts, touched)) ts = pool_ts; else ts = touched; - if (pool->cpu >= 0) { - unsigned long cpu_touched = - READ_ONCE(per_cpu(wq_watchdog_touched_cpu, - pool->cpu)); - if (time_after(cpu_touched, ts)) - ts = cpu_touched; - } - /* did we stall? */ if (time_after(jiffies, ts + thresh)) { lockup_detected = true; @@ -5826,8 +5821,8 @@ notrace void wq_watchdog_touch(int cpu) { if (cpu >= 0) per_cpu(wq_watchdog_touched_cpu, cpu) = jiffies; - else - wq_watchdog_touched = jiffies; + + wq_watchdog_touched = jiffies; } static void wq_watchdog_set_thresh(unsigned long thresh) -- 2.7.4