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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 9DC65C47404 for ; Fri, 4 Oct 2019 17:35:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7880E215EA for ; Fri, 4 Oct 2019 17:35:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570210539; bh=vswXn9bVUS1NjpLa4r3F9UqpE+nv0AHEu7eaTUx/4YA=; h=Date:From:To:Subject:List-ID:From; b=tkojx7x0UX99N3TIgzGzzCFYfNMX5/tw0M+4FZgTlE64fPNJ+2m2MEsZSViU0XqdB gEyQl84yoimNHPfsCb9U6jh8oMPjysV3G5K/WKJBl7WNNjF+lQUCNqsnGfYn5gE9WP FcT390g0ThXQhzGHpJCByuoHKrWlppSh1IhPl9EY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388249AbfJDRfi (ORCPT ); Fri, 4 Oct 2019 13:35:38 -0400 Received: from mail-qt1-f195.google.com ([209.85.160.195]:45028 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387948AbfJDRfi (ORCPT ); Fri, 4 Oct 2019 13:35:38 -0400 Received: by mail-qt1-f195.google.com with SMTP id u40so9596636qth.11 for ; Fri, 04 Oct 2019 10:35:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:subject:message-id:mime-version :content-disposition:user-agent; bh=a144TA2Cr2FVasjy1SZyP/1P9SMWRYxWQqK2LgWfLko=; b=pzYP/mPyt+H2P666eIidvb2nAvhWbgF4v/Io84aPNYmqpoP+ZWHrY0ulTEbIJlraYs OLpqbHnP1EBsrzd9ebRjqEad2CpkV+p+k/LRKd/DHhoAM9bb2iKEnLezEsgHYaFtTrQ8 Am+9APYie1SHv1j4trsQbDMsfbH5+0/q0RpB3nRO5adW+taXLMwzWy6+p9rZH7MUBe+1 yaOl+ZBIontECJe5yQhHOZWM6p0Y0dSR0F4d/7rCjNKFBLu1oD8bjdjZ+KSe95G/s/Vw /vXCDMmUMxga97ujMURtnmNMrVAoj4v63yu19UWEcs0iR9AFhmHfcWi8MRqqkBpZI1fx jpgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:subject:message-id :mime-version:content-disposition:user-agent; bh=a144TA2Cr2FVasjy1SZyP/1P9SMWRYxWQqK2LgWfLko=; b=jsnMwXLhdcc2+iZudIdhcTWxDMOmpnp6QhzYlFa0C8iw3up2sFh8JZnIk0paVlwUcZ gdSW1WNDzFC8hky+OuzR2w601wLxawOxTyTLASEHx4cRfofyzVIsci5HVz07mf+asj1a kuTP3wESWql39FrmsQKN2xKyGRRS+xzahRIHBwbOuWEvvXWE8q5pP6NdiNAkb8Uf5gZ3 TZFnPqtxD9Cv4fWRCvhkjY4wiEUYE+IdPslD0PZBn6i9mzha5kguLfz/Lg46px9Cm6x+ FRSqcwFzviO3In+ocp82XQD2cpt7LXQ+Cuc834oQEZY9pzfpcR11XEQJHNMf6peWPToQ WFKw== X-Gm-Message-State: APjAAAUd3n3OB6TiKmoDxeF3q+GrxNpyYlK+L/s3kEw1tIKlEfvl+TR7 o3XTBGNhL3SC9dgSZaYGV5Q= X-Google-Smtp-Source: APXvYqz0oqBlfhQ77EB8UiEY7M6mHeNtnzsg0NKbUob40PGFg8KylYzwJQqJOePfAf8Ep9S7IAXcPA== X-Received: by 2002:ad4:5604:: with SMTP id ca4mr2965266qvb.50.1570210537389; Fri, 04 Oct 2019 10:35:37 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::91c3]) by smtp.gmail.com with ESMTPSA id d55sm3971449qta.41.2019.10.04.10.35.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 04 Oct 2019 10:35:36 -0700 (PDT) Date: Fri, 4 Oct 2019 10:35:34 -0700 From: Tejun Heo To: Lai Jiangshan , linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: [PATCH wq/for-5.4-fixes] workqueue: more destroy_workqueue() fixes Message-ID: <20191004173534.GA3404308@devbig004.ftw2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >From c29eb85386880750130a01aabf288408a6614d65 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 23 Sep 2019 11:08:58 -0700 Subject: [PATCH] workqueue: more destroy_workqueue() fixes destroy_workqueue() warnings still, at a lower frequency, trigger spuriously. The problem seems to be in-flight operations which haven't reached put_pwq() yet. * Make sanity check grab all the related locks so that it's synchronized against operations which puts pwq at the end. * Always print out the offending pwq. Signed-off-by: Tejun Heo Cc: "Williams, Gerald S" --- Applying to wq/for-5.4-fixes to plug the remaining holes during destruction sanity checks. Thanks. kernel/workqueue.c | 45 +++++++++++++++++++++++++++++++-------------- 1 file changed, 31 insertions(+), 14 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 7f7aa45dac37..4a3c30177b94 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -355,6 +355,7 @@ EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); static int worker_thread(void *__worker); static void workqueue_sysfs_unregister(struct workqueue_struct *wq); +static void show_pwq(struct pool_workqueue *pwq); #define CREATE_TRACE_POINTS #include @@ -4314,6 +4315,22 @@ struct workqueue_struct *alloc_workqueue(const char *fmt, } EXPORT_SYMBOL_GPL(alloc_workqueue); +static bool pwq_busy(struct pool_workqueue *pwq) +{ + int i; + + for (i = 0; i < WORK_NR_COLORS; i++) + if (pwq->nr_in_flight[i]) + return true; + + if ((pwq != pwq->wq->dfl_pwq) && (pwq->refcnt > 1)) + return true; + if (pwq->nr_active || !list_empty(&pwq->delayed_works)) + return true; + + return false; +} + /** * destroy_workqueue - safely terminate a workqueue * @wq: target workqueue @@ -4348,28 +4365,28 @@ void destroy_workqueue(struct workqueue_struct *wq) kfree(rescuer); } - /* sanity checks */ + /* + * Sanity checks - grab all the locks so that we wait for all + * in-flight operations which may do put_pwq(). + */ + mutex_lock(&wq_pool_mutex); mutex_lock(&wq->mutex); for_each_pwq(pwq, wq) { - int i; - - for (i = 0; i < WORK_NR_COLORS; i++) { - if (WARN_ON(pwq->nr_in_flight[i])) { - mutex_unlock(&wq->mutex); - show_workqueue_state(); - return; - } - } - - if (WARN_ON((pwq != wq->dfl_pwq) && (pwq->refcnt > 1)) || - WARN_ON(pwq->nr_active) || - WARN_ON(!list_empty(&pwq->delayed_works))) { + spin_lock_irq(&pwq->pool->lock); + if (WARN_ON(pwq_busy(pwq))) { + pr_warning("%s: %s has the following busy pwq (refcnt=%d)\n", + __func__, wq->name, pwq->refcnt); + show_pwq(pwq); + spin_unlock_irq(&pwq->pool->lock); mutex_unlock(&wq->mutex); + mutex_unlock(&wq_pool_mutex); show_workqueue_state(); return; } + spin_unlock_irq(&pwq->pool->lock); } mutex_unlock(&wq->mutex); + mutex_unlock(&wq_pool_mutex); /* * wq list is used to freeze wq, remove from list after -- 2.17.1