From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754631Ab2L1T6v (ORCPT ); Fri, 28 Dec 2012 14:58:51 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54887 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754236Ab2L1TQw (ORCPT ); Fri, 28 Dec 2012 14:16:52 -0500 Message-Id: <20121228190332.337998711@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Fri, 28 Dec 2012 20:03:41 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Tejun Heo , Xiaotian Feng , Shuah Khan Subject: [ 011/173] workqueue: convert BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s In-Reply-To: <20121228190330.025298996@decadent.org.uk> X-SA-Exim-Connect-IP: 151.217.219.220 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tejun Heo commit fc4b514f2727f74a4587c31db87e0e93465518c3 upstream. 8852aac25e ("workqueue: mod_delayed_work_on() shouldn't queue timer on 0 delay") unexpectedly uncovered a very nasty abuse of delayed_work in megaraid - it allocated work_struct, casted it to delayed_work and then pass that into queue_delayed_work(). Previously, this was okay because 0 @delay short-circuited to queue_work() before doing anything with delayed_work. 8852aac25e moved 0 @delay test into __queue_delayed_work() after sanity check on delayed_work making megaraid trigger BUG_ON(). Although megaraid is already fixed by c1d390d8e6 ("megaraid: fix BUG_ON() from incorrect use of delayed work"), this patch converts BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s so that such abusers, if there are more, trigger warning but don't crash the machine. Signed-off-by: Tejun Heo Cc: Xiaotian Feng [Shuah Khan: This change is back-ported from upstream change that converted BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s.] Tested on Stable Trees: 3.0.x, 3.4.x, 3.6.x Signed-off-by: Shuah Khan Signed-off-by: Ben Hutchings --- kernel/workqueue.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1146,8 +1146,8 @@ int queue_delayed_work_on(int cpu, struc if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) { unsigned int lcpu; - BUG_ON(timer_pending(timer)); - BUG_ON(!list_empty(&work->entry)); + WARN_ON_ONCE(timer_pending(timer)); + WARN_ON_ONCE(!list_empty(&work->entry)); timer_stats_timer_set_start_info(&dwork->timer);