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 713B8C25B0F for ; Sun, 14 Aug 2022 15:49:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241654AbiHNPtm (ORCPT ); Sun, 14 Aug 2022 11:49:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241680AbiHNPsl (ORCPT ); Sun, 14 Aug 2022 11:48:41 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F1DFE091; Sun, 14 Aug 2022 08:35:28 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D8AC2B80B48; Sun, 14 Aug 2022 15:35:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7143C433D6; Sun, 14 Aug 2022 15:35:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660491325; bh=MbuwiAIDCIAhGbfb6UylE+MBmJo/z7UQiz0v3eaRbT0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cOFtlSaHYC0V4dvMkljj9Pjs7KxavG/xOEZzFbl/+qUq6KCzqJjcQnHVFQ2/kh/cZ ELyQlNdfkcwWO6M+bPg4FuhGwZ83XQwbYN44JdbZkZeVtMBYcZVz1P8A1aMyPAMcp7 2AgAcixrVH/BozFg8eBE5PBGO2o1+5nJD5DlXrGiqQxGI6PuTtiZutJQYyInOhvIHF n0SQUE/P62ZUKbsEjHhzLi88FZKtgpFqlw53b3jxEnxGg/WKNj+ROCWRjYQGGKZXtd wYfFGHrpr4wC7M1omawrMPSX7aTBxe7/r5ImyPTLEeo3ZPCxqWBJ1YI3uIbej48YM7 nioV15Ju1X/tg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Logan Gunthorpe , Christoph Hellwig , Song Liu , Jens Axboe , Sasha Levin , linux-raid@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 27/31] md: Notify sysfs sync_completed in md_reap_sync_thread() Date: Sun, 14 Aug 2022 11:34:27 -0400 Message-Id: <20220814153431.2379231-27-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220814153431.2379231-1-sashal@kernel.org> References: <20220814153431.2379231-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Logan Gunthorpe [ Upstream commit 9973f0fa7d20269fe6fefe6333997fb5914449c1 ] 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 Signed-off-by: Song Liu Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/md/md.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 5bd1edbb415b..f0c7a3032242 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9424,6 +9424,7 @@ void md_reap_sync_thread(struct mddev *mddev) 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(mddev); if (mddev->event_work.func) -- 2.35.1