From patchwork Tue May 19 07:12:59 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Hocko X-Patchwork-Id: 6434251 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 86DC19F38D for ; Tue, 19 May 2015 07:13:08 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 90322203AB for ; Tue, 19 May 2015 07:13:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A347A20394 for ; Tue, 19 May 2015 07:13:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752704AbbESHNF (ORCPT ); Tue, 19 May 2015 03:13:05 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:34170 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbbESHNE (ORCPT ); Tue, 19 May 2015 03:13:04 -0400 Received: by wicmc15 with SMTP id mc15so106084605wic.1; Tue, 19 May 2015 00:13:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=YKMdORkuUWCa4PTX4SLVpw0ZCdLnU0USfFC8Zk/P98g=; b=h+3uRoJTFz9ttbKCXo0DJ54KB1HPjB2uAgTENYkPT4Tjes6iiJB/Av8lC8e3PY0v4j LP1dFCNjooEwL/S3gAOX8MjB7M/lIW1vauDlGNTLf6o9cSXc4cm7AY2zhJi9+Z/tG3zI SK/NgruzKqXEfGNvR4KlPRgDsPVHo5ddIIstYKFW+H/MUjQqBDtZOIkTL6vpaFbUrXoG nY4KLyjqiUW8RQ+B4Gp2jXxhpja4CtTLekuqF97X2ydY86Tikovb3XT2qt9vNRcBsrop QX3WRWBb8o+BME2ruutRNCVLfc/siMSeeigNd5GmNAelf5PH6tpa1K0b4bxCAXZFD/L7 JlCA== X-Received: by 10.194.122.200 with SMTP id lu8mr50698042wjb.30.1432019581629; Tue, 19 May 2015 00:13:01 -0700 (PDT) Received: from localhost (nat1.scz.suse.com. [213.151.88.250]) by mx.google.com with ESMTPSA id n1sm15898265wix.0.2015.05.19.00.13.00 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 19 May 2015 00:13:00 -0700 (PDT) Date: Tue, 19 May 2015 09:12:59 +0200 From: Michal Hocko To: Linus Torvalds Cc: Peter Zijlstra , Stephane Eranian , Ulrich Obergfell , Don Zickus , Ingo Molnar , Andrew Morton , "Rafael J. Wysocki" , Kevin Hilman , Ulf Hansson , "linux-pm@vger.kernel.org" , LKML Subject: Re: suspend regression in 4.1-rc1 Message-ID: <20150519071259.GA6847@dhcp22.suse.cz> References: <20150517185041.GA5897@dhcp22.suse.cz> <20150518073046.GO17717@twins.programming.kicks-ass.net> <20150518090336.GA6393@dhcp22.suse.cz> <20150518093150.GC21418@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Mon 18-05-15 10:10:50, Linus Torvalds wrote: > On Mon, May 18, 2015 at 2:31 AM, Peter Zijlstra wrote: > > Subject: watchdog: Fix merge 'conflict' > > > > Two watchdog changes that came through different trees had a non > > conflicting conflict, that is, one changed the semantics of a variable > > but no actual code conflict happened. So the merge appeared fine, but > > the resulting code did not behave as expected. > > Ok, I see that people are still discussing this, but I'll apply it > as-is since I want to get rc4 out the door, and I guess people can > tweak this if there's anything else we want to do longer-term. The final patch from Peter has a typo. Without the following the system deadlocks obviously: --- From 215266efd5e14938d14f0f4258a70fb32f6a455b Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Tue, 19 May 2015 09:07:27 +0200 Subject: [PATCH] watchdog: fix double lock in watchdog_nmi_enable_all ab992dc38f9a ("watchdog: Fix merge 'conflict'") has introduced an obvious deadlock because of a typo. watchdog_proc_mutex should be unlocked on exit. Thanks to Miroslav Benes who was staring at the code with me and noticed this. Signed-off-by: Michal Hocko --- kernel/watchdog.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 506edcc500c4..581a68a04c64 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -621,7 +621,7 @@ void watchdog_nmi_enable_all(void) put_online_cpus(); unlock: - mutex_lock(&watchdog_proc_mutex); + mutex_unlock(&watchdog_proc_mutex); } void watchdog_nmi_disable_all(void)