From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754980AbaDGINr (ORCPT ); Mon, 7 Apr 2014 04:13:47 -0400 Received: from merlin.infradead.org ([205.233.59.134]:39432 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753317AbaDGINn (ORCPT ); Mon, 7 Apr 2014 04:13:43 -0400 Date: Mon, 7 Apr 2014 10:13:36 +0200 From: Peter Zijlstra To: Vladimir Davydov Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, devel@openvz.org, Ingo Molnar Subject: Re: [PATCH -mm 2/3] lockdep: mark rwsem_acquire_read as recursive Message-ID: <20140407081336.GC11096@twins.programming.kicks-ass.net> References: <8c6473e959a4557d8622a6d7ff24888cb3f7512d.1396779337.git.vdavydov@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8c6473e959a4557d8622a6d7ff24888cb3f7512d.1396779337.git.vdavydov@parallels.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 06, 2014 at 07:33:51PM +0400, Vladimir Davydov wrote: > rw_semaphore implementation allows recursing calls to down_read, but > lockdep thinks that it doesn't. As a result, it will complain > false-positively, e.g. if we do not observe some predefined locking > order when taking an rw semaphore for reading and a mutex. > > This patch makes lockdep think rw semaphore is read-recursive, just like > rw spin lock. Uhm no rwsem isn't read recursive.