From patchwork Wed Nov 30 13:21:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Li Nan X-Patchwork-Id: 13059786 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 A2F80C46467 for ; Wed, 30 Nov 2022 13:01:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235364AbiK3NBC (ORCPT ); Wed, 30 Nov 2022 08:01:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234500AbiK3NA6 (ORCPT ); Wed, 30 Nov 2022 08:00:58 -0500 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EDFF4E421; Wed, 30 Nov 2022 05:00:56 -0800 (PST) Received: from dggpeml500021.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4NMfPR28XyzJp39; Wed, 30 Nov 2022 20:57:31 +0800 (CST) Received: from dggpeml500003.china.huawei.com (7.185.36.200) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 30 Nov 2022 21:00:54 +0800 Received: from huawei.com (10.175.127.227) by dggpeml500003.china.huawei.com (7.185.36.200) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 30 Nov 2022 21:00:54 +0800 From: Li Nan To: , , CC: , , , , , Subject: [PATCH -next v2 8/9] block: fix null-pointer dereference in ioc_pd_init Date: Wed, 30 Nov 2022 21:21:55 +0800 Message-ID: <20221130132156.2836184-9-linan122@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221130132156.2836184-1-linan122@huawei.com> References: <20221130132156.2836184-1-linan122@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500003.china.huawei.com (7.185.36.200) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Remove block device when iocost is initializing may cause null-pointer dereference: CPU1 CPU2 ioc_qos_write blkcg_conf_open_bdev blkdev_get_no_open kobject_get_unless_zero blk_iocost_init rq_qos_add del_gendisk rq_qos_exit q->rq_qos = rqos->next //iocost is removed from q->roqs blkcg_activate_policy pd_init_fn ioc_pd_init ioc = q_to_ioc(blkg->q) //cant find iocost and return null Fix problem by moving rq_qos_exit() to disk_release(). ioc_qos_write() get bd_device.kobj in blkcg_conf_open_bdev(), so disk_release will not be actived until iocost initialization is complited. Signed-off-by: Li Nan --- block/genhd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/genhd.c b/block/genhd.c index dcf200bcbd3e..0db440bbfefb 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -656,7 +656,6 @@ void del_gendisk(struct gendisk *disk) elevator_exit(q); mutex_unlock(&q->sysfs_lock); } - rq_qos_exit(q); blk_mq_unquiesce_queue(q); /* @@ -1168,6 +1167,7 @@ static void disk_release(struct device *dev) !test_bit(GD_ADDED, &disk->state)) blk_mq_exit_queue(disk->queue); + rq_qos_exit(disk->queue); blkcg_exit_disk(disk); bioset_exit(&disk->bio_split);