From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 553216B026E for ; Wed, 18 Jan 2017 09:13:02 -0500 (EST) Received: by mail-pg0-f70.google.com with SMTP id d185so17892221pgc.2 for ; Wed, 18 Jan 2017 06:13:02 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id l59si359224plb.85.2017.01.18.06.13.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Jan 2017 06:13:01 -0800 (PST) Date: Wed, 18 Jan 2017 15:12:55 +0100 From: Peter Zijlstra Subject: Re: [PATCH v4 15/15] lockdep: Crossrelease feature documentation Message-ID: <20170118141255.GE6515@twins.programming.kicks-ass.net> References: <1481260331-360-1-git-send-email-byungchul.park@lge.com> <1481260331-360-16-git-send-email-byungchul.park@lge.com> <20170118064230.GF15084@tardis.cn.ibm.com> <20170118105346.GL3326@X58A-UD3R> <20170118110317.GC6515@twins.programming.kicks-ass.net> <20170118115428.GM3326@X58A-UD3R> <20170118120757.GD6515@twins.programming.kicks-ass.net> <008101d27184$7d3cbd00$77b63700$@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <008101d27184$7d3cbd00$77b63700$@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: "byungchul.park" Cc: 'Boqun Feng' , mingo@kernel.org, tglx@linutronix.de, walken@google.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, npiggin@gmail.com On Wed, Jan 18, 2017 at 09:14:59PM +0900, byungchul.park wrote: > +Example 3: > + > + CONTEXT X CONTEXT Y > + --------- --------- > + mutex_lock A > + mutex_lock A > + mutex_unlock A > + wait_for_complete B /* DEADLOCK */ Each line (across both columns) is a distinct point in time after the line before. Therefore, this states that "mutex_unlock A" happens before "wait_for_completion B", which is clearly impossible. You don't have to remove everything after mutex_lock A, but the unlock must not happen before context Y does the unlock. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org