From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: 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 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> (sfid-20180821_140330_094925_D662ADF1) In-Reply-To: <20180821120317.4115-1-johannes@sipsolutions.net> References: <20180821120317.4115-1-johannes@sipsolutions.net> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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