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 6831CECAAD3 for ; Fri, 2 Sep 2022 01:01:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235262AbiIBBBp (ORCPT ); Thu, 1 Sep 2022 21:01:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235184AbiIBBBJ (ORCPT ); Thu, 1 Sep 2022 21:01:09 -0400 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77F28A59A7; Thu, 1 Sep 2022 18:00:59 -0700 (PDT) Subject: Re: [PATCH -next 2/3] md/raid10: convert resync_lock to use seqlock DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1662080457; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=u7yAk3VxuKsLyw3p8RI9MaAyfnhE92URrz7dok6zTmk=; b=r/3L/CJXqUjk7tUdlFTR7a8Ot2uYLZ8hw4MOvErI29cFz8cWZyOYUQp5eL0ym5Rtg8CIru 3PFZMgb3d+J+h5gzAVF3gaqWG/jRZIEJhmdxSfyRoSD7dTZw/mi13E6mHbjxd7h71cMI7m vlmOWZkjGksba7d5LUuCo/NU1/uapJs= To: Logan Gunthorpe , Yu Kuai , song@kernel.org Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yi.zhang@huawei.com References: <20220829131502.165356-1-yukuai1@huaweicloud.com> <20220829131502.165356-3-yukuai1@huaweicloud.com> <04128618-962f-fd4e-64a9-09ecf7f83776@deltatee.com> <917c01c1-1e2b-66f9-69f1-ed706b7ffc8f@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Guoqing Jiang Message-ID: <8b21f188-78ef-edbb-d2eb-3a9d74a6e84d@linux.dev> Date: Fri, 2 Sep 2022 09:00:54 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On 9/2/22 8:56 AM, Logan Gunthorpe wrote: > > On 2022-09-01 18:49, Guoqing Jiang wrote: >> >> On 9/2/22 2:41 AM, Logan Gunthorpe wrote: >>> Hi, >>> >>> On 2022-08-29 07:15, Yu Kuai wrote: >>>> From: Yu Kuai >>>> >>>> Currently, wait_barrier() will hold 'resync_lock' to read >>>> 'conf->barrier', >>>> and io can't be dispatched until 'barrier' is dropped. >>>> >>>> Since holding the 'barrier' is not common, convert 'resync_lock' to use >>>> seqlock so that holding lock can be avoided in fast path. >>>> >>>> Signed-off-by: Yu Kuai >>> I've found some lockdep issues starting with this patch in md-next while >>> running mdadm tests (specifically 00raid10 when run about 10 times in a >>> row). >>> >>> I've seen a couple different lock dep errors. The first seems to be >>> reproducible on this patch, then it possibly changes to the second on >>> subsequent patches. Not sure exactly. >> That's why I said "try mdadm test suites too to avoid regression." ... > You may have to run it multiple times, a single run tends not to catch > all errors. I had to loop the noted test 10 times to be sure I hit this > every time when I did the simple bisect. > > And ensure that all the debug options are on when you run it (take a > look at the Kernel Hacking section in menuconfig). You won't hit this > bug without at least CONFIG_PROVE_LOCKING=y. Yes,  we definitely need to enable the option to test change for locking stuffs. Thanks, Guoqing