From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH 13/26] locking: Add non-fatal spin lock assert Date: Thu, 4 Sep 2014 07:14:11 +0200 Message-ID: <20140904051411.GA27350@gmail.com> References: <1409693975-1028-1-git-send-email-peter@hurleysoftware.com> <1409693975-1028-14-git-send-email-peter@hurleysoftware.com> <20140903092723.GA4783@worktop.ger.corp.intel.com> <5406F964.6060900@hurleysoftware.com> <20140903144029.GA7083@twins.programming.kicks-ass.net> <54072A99.1080306@hurleysoftware.com> <20140903150729.GA7436@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-we0-f170.google.com ([74.125.82.170]:62125 "EHLO mail-we0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751332AbaIDFOQ (ORCPT ); Thu, 4 Sep 2014 01:14:16 -0400 Content-Disposition: inline In-Reply-To: <20140903150729.GA7436@twins.programming.kicks-ass.net> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Peter Zijlstra Cc: Peter Hurley , Greg Kroah-Hartman , Jiri Slaby , One Thousand Gnomes , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner * Peter Zijlstra wrote: > On Wed, Sep 03, 2014 at 10:50:01AM -0400, Peter Hurley wrote: > > So a lockdep-only assert is unlikely to draw attention to existing bugs, > > especially in established drivers. > > By the same logic lockdep will not find locking errors in established > drivers. Indeed, this patch is ill-advised in several ways: - it extends an API variant that we want to phase - emits a warning even if say lockdep has already emitted a warning and locking state is not guaranteed to be consistent. - makes the kernel more expensive once fully debugged, in that non-fatal checks are unconditional. Also please submit locking related patches as standalone series to the locking subsystem, not embedded in an unrelated series. Thanks, Ingo