Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751568AbdGMLM2 (ORCPT ); Thu, 13 Jul 2017 07:12:28 -0400 Received: from merlin.infradead.org ([205.233.59.134]:43450 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751079AbdGMLM0 (ORCPT ); Thu, 13 Jul 2017 07:12:26 -0400 Date: Thu, 13 Jul 2017 13:12:09 +0200 From: Peter Zijlstra To: Byungchul Park Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, willy@infradead.org, npiggin@gmail.com, kernel-team@lge.com Subject: Re: [PATCH v7 06/16] lockdep: Detect and handle hist_lock ring buffer overwrite Message-ID: <20170713111209.ji6w3trt45icpuf6@hirez.programming.kicks-ass.net> References: <1495616389-29772-7-git-send-email-byungchul.park@lge.com> <20170711161232.GB28975@worktop> <20170712020053.GB20323@X58A-UD3R> <20170712075617.o2jds2giuoqxjqic@hirez.programming.kicks-ass.net> <20170713020745.GG20323@X58A-UD3R> <20170713081442.GA439@worktop> <20170713085746.GH20323@X58A-UD3R> <20170713095052.dssev34f7c43vlok@hirez.programming.kicks-ass.net> <20170713100953.GI20323@X58A-UD3R> <20170713102905.ysrvn7td6ryt4jaj@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170713102905.ysrvn7td6ryt4jaj@hirez.programming.kicks-ass.net> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 709 Lines: 32 On Thu, Jul 13, 2017 at 12:29:05PM +0200, Peter Zijlstra wrote: > On Thu, Jul 13, 2017 at 07:09:53PM +0900, Byungchul Park wrote: > > On Thu, Jul 13, 2017 at 11:50:52AM +0200, Peter Zijlstra wrote: > > > wait_for_completion(&C); > > > atomic_inc_return(); > > > > > > mutex_lock(A1); > > > mutex_unlock(A1); > > > > > > > > > > > > spin_lock(B1); > > > spin_unlock(B1); > > > > > > ... > > > > > > spin_lock(B64); > > > spin_unlock(B64); > > > > > > > > > Also consider the alternative: spin_lock(D); spin_unlock(D); complete(&C); in which case the context test will also not work.