From patchwork Tue Aug 21 12:03:17 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 10571409 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C3335921 for ; Tue, 21 Aug 2018 12:03:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B7AAB29E0D for ; Tue, 21 Aug 2018 12:03:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AAEEF29F54; Tue, 21 Aug 2018 12:03:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3083529AC9 for ; Tue, 21 Aug 2018 12:03:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727116AbeHUPXU (ORCPT ); Tue, 21 Aug 2018 11:23:20 -0400 Received: from s3.sipsolutions.net ([144.76.43.62]:59498 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726932AbeHUPXU (ORCPT ); Tue, 21 Aug 2018 11:23:20 -0400 Received: by sipsolutions.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.91) (envelope-from ) id 1fs5Nd-00017c-7M; Tue, 21 Aug 2018 14:03:25 +0200 From: Johannes Berg To: Tejun Heo , Lai Jiangshan Cc: linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, Johannes Berg Subject: [PATCH 2/2] workqueue: create lockdep dependency in flush_work() Date: Tue, 21 Aug 2018 14:03:17 +0200 Message-Id: <20180821120317.4115-3-johannes@sipsolutions.net> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180821120317.4115-1-johannes@sipsolutions.net> References: <20180821120317.4115-1-johannes@sipsolutions.net> Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Johannes Berg In flush_work(), we need to create a lockdep dependency so that the following scenario is appropriately tagged as a problem: work_function() { mutex_lock(&mutex); ... } other_function() { mutex_lock(&mutex); flush_work(&work); // or cancel_work_sync(&work); } This is a problem since the work might be running and be blocked on trying to acquire the mutex. Signed-off-by: Johannes Berg --- kernel/workqueue.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index a6c2b823f348..29d4d84ba512 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2852,6 +2852,11 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, might_sleep(); + if (!from_cancel) { + lock_map_acquire(&work->lockdep_map); + lock_map_release(&work->lockdep_map); + } + local_irq_disable(); pool = get_work_pool(work); if (!pool) {