From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B4F6C43334 for ; Mon, 20 Jun 2022 14:51:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242621AbiFTOu4 (ORCPT ); Mon, 20 Jun 2022 10:50:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241048AbiFTOuc (ORCPT ); Mon, 20 Jun 2022 10:50:32 -0400 Received: from outbound-smtp29.blacknight.com (outbound-smtp29.blacknight.com [81.17.249.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBA62C41 for ; Mon, 20 Jun 2022 07:09:53 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp29.blacknight.com (Postfix) with ESMTPS id 4E1A118E00A for ; Mon, 20 Jun 2022 15:09:52 +0100 (IST) Received: (qmail 15998 invoked from network); 20 Jun 2022 14:09:52 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.198.246]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 20 Jun 2022 14:09:51 -0000 Date: Mon, 20 Jun 2022 15:09:50 +0100 From: Mel Gorman To: Waiman Long Cc: Zhenhua Ma , Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng , LKML , Michal Hocko Subject: Re: Lockups due to "locking/rwsem: Make handoff bit handling more consistent" Message-ID: <20220620140950.GB15453@techsingularity.net> References: <20220617134325.GC30825@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 17, 2022 at 10:29:20AM -0400, Waiman Long wrote: > > The C file and shell script to run it are attached. > > > Thanks for the reproducer and I will try to reproduce it locally. > > It is a known issue that I have receive similar report from an Oracle > engineer. That is the reason I posted commit 1ee326196c66 ("locking/rwsem: > Always try to wake waiters in out_nolock path") that was merged in v5.19. I > believe it helps but it may not be able to eliminate all possible race > conditions. To make rwsem behave more like before commit d257cc8cb8d5 > ("locking/rwsem: Make handoff bit handling more consistent"), I posted a > follow-up patch > > https://lore.kernel.org/lkml/20220427173124.1428050-1-longman@redhat.com/ > > But it hasn't gotten review yet. > FWIW, the patch passed the test case when applied to both 5.18 and 5.19-rc3. -- Mel Gorman SUSE Labs