From nobody Tue Feb 10 17:35:03 2026 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 D62DCEB64DC for ; Thu, 6 Jul 2023 08:39:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231467AbjGFIjB (ORCPT ); Thu, 6 Jul 2023 04:39:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229718AbjGFIiy (ORCPT ); Thu, 6 Jul 2023 04:38:54 -0400 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28E851BC3; Thu, 6 Jul 2023 01:38:53 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4QxVLH2QXhz4f3jY4; Thu, 6 Jul 2023 16:38:47 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.104.67]) by APP4 (Coremail) with SMTP id gCh0CgA34qWWfaZkk+xQNQ--.47999S6; Thu, 06 Jul 2023 16:38:49 +0800 (CST) From: Yu Kuai To: song@kernel.org, guoqing.jiang@linux.dev, neilb@suse.com Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com, yangerkun@huawei.com Subject: [PATCH -next 2/2] md/md-bitmap: hold 'reconfig_mutex' in backlog_store() Date: Thu, 6 Jul 2023 16:37:27 +0800 Message-Id: <20230706083727.608914-3-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230706083727.608914-1-yukuai1@huaweicloud.com> References: <20230706083727.608914-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgA34qWWfaZkk+xQNQ--.47999S6 X-Coremail-Antispam: 1UD129KBjvJXoW7Kr1kWFW7Xw48ZF1fArW3trb_yoW8Xw13pr s7KFy5Grn5tFy3tr1DXF4DWFy5XanrXr9rtrW3W3W5uFy0vr9xKFyrWa4Yyryxta4fGF15 Xr45WFykAayrJrJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9m14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCF04k20xvY0x0EwIxGrwCFx2 IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v2 6r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67 AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IY s7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr 0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUc6pPUUUUU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Yu Kuai Several reasons why 'reconfig_mutex' should be held: 1) rdev_for_each() is not safe to be called without the lock, because rdev can be removed concurrently. 2) mddev_destroy_serial_pool() and mddev_create_serial_pool() should not be called concurrently. 3) mddev_suspend() from mddev_destroy/create_serial_pool() should be protected by the lock. Fixes: 10c92fca636e ("md-bitmap: create and destroy wb_info_pool with the c= hange of backlog") Signed-off-by: Yu Kuai --- drivers/md/md-bitmap.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index 1f3339961159..6f9ff14971f9 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2546,6 +2546,10 @@ backlog_store(struct mddev *mddev, const char *buf, = size_t len) if (backlog > COUNTER_MAX) return -EINVAL; =20 + rv =3D mddev_lock(mddev); + if (rv) + return rv; + /* * Without write mostly device, it doesn't make sense to set * backlog for max_write_behind. @@ -2559,6 +2563,7 @@ backlog_store(struct mddev *mddev, const char *buf, s= ize_t len) if (!has_write_mostly) { pr_warn_ratelimited("%s: can't set backlog, no write mostly device avail= able\n", mdname(mddev)); + mddev_unlock(mddev); return -EINVAL; } =20 @@ -2574,6 +2579,8 @@ backlog_store(struct mddev *mddev, const char *buf, s= ize_t len) } if (old_mwb !=3D backlog) md_bitmap_update_sb(mddev->bitmap); + + mddev_unlock(mddev); return len; } =20 --=20 2.39.2