From patchwork Sat Dec 17 03:09:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 13075773 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 9F2B5C4332F for ; Sat, 17 Dec 2022 02:48:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230213AbiLQCse (ORCPT ); Fri, 16 Dec 2022 21:48:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230207AbiLQCsc (ORCPT ); Fri, 16 Dec 2022 21:48:32 -0500 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A36E4A453; Fri, 16 Dec 2022 18:48:30 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4NYr4n1m64z4f3lXl; Sat, 17 Dec 2022 10:48:25 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP4 (Coremail) with SMTP id gCh0CgB3m9j5LZ1jmxh7CQ--.11469S8; Sat, 17 Dec 2022 10:48:28 +0800 (CST) From: Yu Kuai To: tj@kernel.org, hch@infradead.org, josef@toxicpanda.com, axboe@kernel.dk Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yukuai1@huaweicloud.com, yi.zhang@huawei.com Subject: [PATCH -next 4/4] blk-cgroup: synchronize del_gendisk() with configuring cgroup policy Date: Sat, 17 Dec 2022 11:09:08 +0800 Message-Id: <20221217030908.1261787-5-yukuai1@huaweicloud.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221217030908.1261787-1-yukuai1@huaweicloud.com> References: <20221217030908.1261787-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: gCh0CgB3m9j5LZ1jmxh7CQ--.11469S8 X-Coremail-Antispam: 1UD129KBjvJXoWxur1DZrykJF4kCw4rXrW3Awb_yoW5Jw18pa 9IgF13CrWIgrsrZa1DGa1fZrsavw40gr1fA3yfA3yayrW7Kr1IvF1kAF9rZrWfZFsxJrsx Xr4FgrZ0kr1UCw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPF14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JF0E3s1l82xGYI kIc2x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2 z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F 4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq 3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7 IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4U M4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2 kIc2xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E 14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIx kGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAF wI0_Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJV W8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUF18B UUUUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Yu Kuai iocost is initialized when it's configured the first time, and iocost initializing can race with del_gendisk(), which will cause null pointer dereference: t1 t2 ioc_qos_write blk_iocost_init rq_qos_add del_gendisk rq_qos_exit //iocost is removed from q->roqs blkcg_activate_policy pd_init_fn ioc_pd_init ioc = q_to_ioc(blkg->q) //can't find iocost and return null Fix the problem by adding a new mutex in request_queue, and use it to synchronize rq_qos_exit() from del_gendisk() with configuring cgroup policy. Signed-off-by: Yu Kuai --- block/blk-cgroup.c | 3 +++ block/blk-rq-qos.c | 8 ++++++++ include/linux/blkdev.h | 1 + 3 files changed, 12 insertions(+) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index ad612148cf3b..8dcdaacb52a1 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -658,12 +658,14 @@ struct block_device *blkcg_conf_open_bdev(char **inputp) return ERR_PTR(-ENODEV); } + mutex_lock(&bdev->bd_queue->blkcg_pols_lock); *inputp = input; return bdev; } void blkcg_conf_close_bdev(struct block_device *bdev) { + mutex_unlock(&bdev->bd_queue->blkcg_pols_lock); blkdev_put_no_open(bdev); } @@ -1277,6 +1279,7 @@ int blkcg_init_disk(struct gendisk *disk) int ret; INIT_LIST_HEAD(&q->blkg_list); + mutex_init(&q->blkcg_pols_lock); new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL); if (!new_blkg) diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c index efffc6fa55db..86bccdfa1a43 100644 --- a/block/blk-rq-qos.c +++ b/block/blk-rq-qos.c @@ -290,6 +290,10 @@ void rq_qos_exit(struct request_queue *q) { struct rq_qos *rqos; +#ifdef CONFIG_BLK_CGROUP + mutex_lock(&q->blkcg_pols_lock); +#endif + spin_lock_irq(&q->queue_lock); rqos = q->rq_qos; q->rq_qos = NULL; @@ -300,4 +304,8 @@ void rq_qos_exit(struct request_queue *q) rqos->ops->exit(rqos); rqos = rqos->next; } while (rqos); + +#ifdef CONFIG_BLK_CGROUP + mutex_unlock(&q->blkcg_pols_lock); +#endif } diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 301cf1cf4f2f..824d68a41a83 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -484,6 +484,7 @@ struct request_queue { DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS); struct blkcg_gq *root_blkg; struct list_head blkg_list; + struct mutex blkcg_pols_lock; #endif struct queue_limits limits;