Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752274AbdLFXqc (ORCPT ); Wed, 6 Dec 2017 18:46:32 -0500 Received: from merlin.infradead.org ([205.233.59.134]:33600 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950AbdLFXqb (ORCPT ); Wed, 6 Dec 2017 18:46:31 -0500 Date: Thu, 7 Dec 2017 00:46:22 +0100 From: Peter Zijlstra To: Julia Cartwright Cc: Thomas Gleixner , Gratian Crisan , linux-kernel@vger.kernel.org, Darren Hart , Ingo Molnar Subject: Re: PI futexes + lock stealing woes Message-ID: <20171206234622.GZ3326@worktop> References: <20171129175605.GA863@jcartwri.amer.corp.natinst.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171129175605.GA863@jcartwri.amer.corp.natinst.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 575 Lines: 13 On Wed, Nov 29, 2017 at 11:56:05AM -0600, Julia Cartwright wrote: > fixup_owner() used to have additional seemingly relevant checks in place > that were removed 73d786bd043eb ("futex: Rework inconsistent > rt_mutex/futex_q state"). *groan*... yes. I completely missed that extra case also applied to requeue_pi (requeue always did hurt my brain). I got as far as actually understanding the problem; but its near 1am and I desperately need a sleep, I'll see if I can come up with a solution tomorrow. I just wanted to let you know I finally got around to looking at this..