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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 53D3BC4321D for ; Tue, 21 Aug 2018 12:38:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F2CD2151D for ; Tue, 21 Aug 2018 12:38:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F2CD2151D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sipsolutions.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727592AbeHUP6s (ORCPT ); Tue, 21 Aug 2018 11:58:48 -0400 Received: from s3.sipsolutions.net ([144.76.43.62]:59886 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727499AbeHUP6r (ORCPT ); Tue, 21 Aug 2018 11:58:47 -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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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) { -- 2.14.4