From patchwork Thu May 26 16:36:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 12862524 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 B207EC4332F for ; Thu, 26 May 2022 16:36:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348161AbiEZQg0 (ORCPT ); Thu, 26 May 2022 12:36:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348132AbiEZQgX (ORCPT ); Thu, 26 May 2022 12:36:23 -0400 Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B79D48E61; Thu, 26 May 2022 09:36:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:MIME-Version:References:In-Reply-To: Message-Id:Date:Cc:To:From:content-disposition; bh=tiDb5N7DtJWgf5i+viE/JdrxQoObOCh/lk7c62dUGdI=; b=H3fM8eJI/0Qi9l/+we2qC4Mb3x L1PRPZ/Eyb2qmb6zyuF5YCumWK0SqoNfzrwmsjoYUsd6AMFuyFcVgXrPf5kOWkHUUeGvjO4iNJm4X sn0Q+bxbp+wvUOAT8WrTGhmVcIPmcIRBeiMQ8gxiF7EJASkZ+zghGMhrsZuxJ58ZdED4GLwvNXRk4 gUQUxzAcorulWSm3HU/DFK//cF3Q2Uj2J5kei2+jhBN2I1cAzNXBktg+PlC7IqY/+F8Xos4ZH5M4o klHseeSuxmsyCAwnhonR/SQ3PThrtBLE17kuxG2fMNJCaWVT7cohWKym2XGoEbTeorktyiagvk90u 6YJ38UvA==; Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nuGTD-008A7T-HN; Thu, 26 May 2022 10:36:21 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.94.2) (envelope-from ) id 1nuGTB-0008Y3-C7; Thu, 26 May 2022 10:36:17 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, Song Liu Cc: Christoph Hellwig , Donald Buczek , Guoqing Jiang , Xiao Ni , Stephen Bates , Martin Oliveira , David Sloan , Logan Gunthorpe , Christoph Hellwig Date: Thu, 26 May 2022 10:36:04 -0600 Message-Id: <20220526163604.32736-18-logang@deltatee.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220526163604.32736-1-logang@deltatee.com> References: <20220526163604.32736-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, song@kernel.org, hch@infradead.org, buczek@molgen.mpg.de, guoqing.jiang@linux.dev, xni@redhat.com, sbates@raithlin.com, Martin.Oliveira@eideticom.com, David.Sloan@eideticom.com, logang@deltatee.com, hch@lst.de X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH v2 17/17] md: Notify sysfs sync_completed in md_reap_sync_thread() X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org The mdadm test 07layouts randomly produces a kernel hung task deadlock. The deadlock is caused by the suspend_lo/suspend_hi files being set by the mdadm background process during reshape and not being cleared because the process hangs. (Leaving aside the issue of the fragility of freezing kernel tasks by buggy userspace processes...) When the background mdadm process hangs it, is waiting (without a timeout) on a change to the sync_completed file signalling that the reshape has completed. The process is woken up a couple times when the reshape finishes but it is woken up before MD_RECOVERY_RUNNING is cleared so sync_completed_show() reports 0 instead of "none". To fix this, notify the sysfs file in md_reap_sync_thread() after MD_RECOVERY_RUNNING has been cleared. This wakes up mdadm and causes it to continue and write to suspend_lo/suspend_hi to allow IO to continue. Signed-off-by: Logan Gunthorpe Reviewed-by: Christoph Hellwig --- drivers/md/md.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 2be429874d18..2c07c9508222 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9476,6 +9476,7 @@ void md_reap_sync_thread(struct mddev *mddev, bool reconfig_mutex_held) wake_up(&resync_wait); /* flag recovery needed just to double check */ set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + sysfs_notify_dirent_safe(mddev->sysfs_completed); sysfs_notify_dirent_safe(mddev->sysfs_action); md_new_event(); if (mddev->event_work.func)