From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753831AbbIPLBA (ORCPT ); Wed, 16 Sep 2015 07:01:00 -0400 Received: from casper.infradead.org ([85.118.1.10]:51453 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751648AbbIPLA7 (ORCPT ); Wed, 16 Sep 2015 07:00:59 -0400 Date: Wed, 16 Sep 2015 12:55:35 +0200 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Tim Spriggs , davej@codemonkey.org.uk, sasha.levin@oracle.com, linux-kernel@vger.kernel.org Subject: Re: unpinning an unpinned lock Message-ID: <20150916105535.GD3816@twins.programming.kicks-ass.net> References: <20150915214244.GS4029@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150915214244.GS4029@linux.vnet.ibm.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 Tue, Sep 15, 2015 at 02:42:44PM -0700, Paul E. McKenney wrote: > > All nodes report from: kernel/locking/lockdep.c:3497 lock_unpin_lock+0xed/0xf0() > > > [] lock_unpin_lock+0xed/0xf0 > > [] pick_next_task_fair+0x51/0x220 > > [] __schedule+0x12c/0x990 > > [] schedule+0x3e/0x80 > > [] lock_unpin_lock+0xed/0xf0 > > [] __schedule+0x3b1/0x990 > > [] schedule+0x3e/0x80 Right, Sasha was reporting these too, I've not been able to reproduce and neither have I been able to make sense of the extra debug bits Sasha generated :/ I've even completely reimplemented the feature from scratch and compared to see if I missed something -- either I'm being very consistent with my mistakes or something else is happening. In any case, I'll have another go at tackling this, otherwise I'll have to disable this warning for now. Note that this lockdep 'feature' is pure annotation, no actual logic was changed.