From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752873Ab1C2MtG (ORCPT ); Tue, 29 Mar 2011 08:49:06 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:59059 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752231Ab1C2MtF (ORCPT ); Tue, 29 Mar 2011 08:49:05 -0400 X-Authority-Analysis: v=1.1 cv=pN6kzQkhXdmdOr6Akjoh3kGBD/S3UyPMKQp53EJY+ro= c=1 sm=0 a=D48tj3hmCtUA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=DDJ3mrVtAAAA:8 a=_lhN5bRkVMF5Vi1OfOkA:9 a=WEVemJ1CzUeo4M41oMCiseDMZPcA:4 a=PUjeQqilurYA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [RFC] seqlock,lockdep: Add lock primitives to read_seqbegin(). From: Steven Rostedt To: Tetsuo Handa Cc: peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org In-Reply-To: <201103290430.p2T4UhLA081016@www262.sakura.ne.jp> References: <201103261312.AEJ01293.OVFJFSLtHOFOMQ@I-love.SAKURA.ne.jp> <20110328171217.GA8529@home.goodmis.org> <201103290430.p2T4UhLA081016@www262.sakura.ne.jp> Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 29 Mar 2011 08:49:02 -0400 Message-ID: <1301402942.14261.266.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-03-29 at 13:30 +0900, Tetsuo Handa wrote: > I made a small test module (which should work on 2.6.38.2). Thanks! I'll take a look at this later today. > > ---------- locktest.c start ---------- [...] > ---------- Makefile end ---------- > > Below are my testcases and results (gcc 3.3 / x86_32). > Kernel config is at http://I-love.SAKURA.ne.jp/tmp/config-2.6.38.2 . > > ---------- Testcase 1 ---------- > > # cat /proc/locktest1 > # cat /proc/locktest2 > # cat /proc/locktest1 > # cat /proc/locktest2 > # cat /proc/locktest1 > # cat /proc/locktest2 > > showed nothing in dmesg. > > ---------- Testcase 2 ---------- > > # cat /proc/locktest1 > # cat /proc/locktest2 > # cat /proc/locktest3 > > showed below message. > > ======================================================= > [ INFO: possible circular locking dependency detected ] > 2.6.38.2 #1 > ------------------------------------------------------- [...] > Well... did I misuse spinlock primitives in read_seqbegin2()? > Anyway, lockdep should catch testcase 1. Strange. I'll investigate this further. Thanks, -- Steve