From patchwork Mon Jun 3 12:58:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 13683798 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE86112C552; Mon, 3 Jun 2024 13:00:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.255 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717419661; cv=none; b=PKhPk2MjAvdVKBnvOt67k/35/vIcH7EKkjhUnQjw4XGGNv9afCsnBdvGNUqhlU/I2lHoNCSCIwmmt2Aaes+xhfO/XHFhSRSgktVliRS53dYxmSsjrYEFOmtgoeaymdDoxPjTQGtE1qet3MszNc5D54BV+FbeUmNLpUuIN44vhoo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717419661; c=relaxed/simple; bh=DbKL2DpCNxLJE7j01bpvEj8WJhxVsUr+mlsQyFYMnDg=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nv7jiOoHCopu76v+9bgF5eWK6LAkyXsEdOtRG78MHPCSkcm2nCYiJMXMJ1VgTa9f/1vSpU6RPjjkpYzmgI6qNhVuDsUuC4iLQw+cTJptOzyGspzX2x2tr6Fh/QRB7W+SiOqh8DM3HmZcDIN1CUmf2b0CwXRrslsf9Fsf6G6VX2g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.255 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.105]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4VtDJb5Yjwz1S98n; Mon, 3 Jun 2024 20:57:03 +0800 (CST) Received: from kwepemm600009.china.huawei.com (unknown [7.193.23.164]) by mail.maildlp.com (Postfix) with ESMTPS id B8A9E140413; Mon, 3 Jun 2024 21:00:42 +0800 (CST) Received: from huawei.com (10.175.104.67) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Mon, 3 Jun 2024 20:58:20 +0800 From: Yu Kuai To: , , , , , , CC: , , , , , , Subject: [PATCH 12/12] md/raid5: avoid BUG_ON() while continue reshape after reassembling Date: Mon, 3 Jun 2024 20:58:15 +0800 Message-ID: <20240603125815.2199072-13-yukuai3@huawei.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240603125815.2199072-1-yukuai3@huawei.com> References: <20240603125815.2199072-1-yukuai3@huawei.com> Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600009.china.huawei.com (7.193.23.164) Currently, mdadm support --revert-reshape to abort the reshape while reassembling, as the test 07revert-grow. However, following BUG_ON() can be triggerred by the test: kernel BUG at drivers/md/raid5.c:6278! invalid opcode: 0000 [#1] PREEMPT SMP PTI irq event stamp: 158985 CPU: 6 PID: 891 Comm: md0_reshape Not tainted 6.9.0-03335-g7592a0b0049a #94 RIP: 0010:reshape_request+0x3f1/0xe60 Call Trace: raid5_sync_request+0x43d/0x550 md_do_sync+0xb7a/0x2110 md_thread+0x294/0x2b0 kthread+0x147/0x1c0 ret_from_fork+0x59/0x70 ret_from_fork_asm+0x1a/0x30 Root cause is that --revert-reshape update the raid_disks from 5 to 4, while reshape position is still set, and after reassembling the array, reshape position will be read from super block, then during reshape the checking of 'writepos' that is caculated by old reshape position will fail. Fix this panic the easy way first, by converting the BUG_ON() to WARN_ON(), and stop the reshape if checkings fail. Noted that mdadm must fix --revert-shape as well, and probably md/raid should enhance metadata validation as well, however this means reassemble will fail and there must be user tools to fix the wrong metadata. Signed-off-by: Yu Kuai --- drivers/md/raid5.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 69a083ca41a3..d4c30a94e4e4 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6255,7 +6255,9 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk safepos = conf->reshape_safe; sector_div(safepos, data_disks); if (mddev->reshape_backwards) { - BUG_ON(writepos < reshape_sectors); + if (WARN_ON(writepos < reshape_sectors)) + return MaxSector; + writepos -= reshape_sectors; readpos += reshape_sectors; safepos += reshape_sectors; @@ -6273,14 +6275,18 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk * to set 'stripe_addr' which is where we will write to. */ if (mddev->reshape_backwards) { - BUG_ON(conf->reshape_progress == 0); + if (WARN_ON(conf->reshape_progress == 0)) + return MaxSector; + stripe_addr = writepos; - BUG_ON((mddev->dev_sectors & - ~((sector_t)reshape_sectors - 1)) - - reshape_sectors - stripe_addr - != sector_nr); + if (WARN_ON((mddev->dev_sectors & + ~((sector_t)reshape_sectors - 1)) - + reshape_sectors - stripe_addr != sector_nr)) + return MaxSector; } else { - BUG_ON(writepos != sector_nr + reshape_sectors); + if (WARN_ON(writepos != sector_nr + reshape_sectors)) + return MaxSector; + stripe_addr = sector_nr; }