From nobody Wed Sep 17 17:51:09 2025 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 4B6CAC4332F for ; Sat, 17 Dec 2022 02:48:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229639AbiLQCsk (ORCPT ); Fri, 16 Dec 2022 21:48:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229950AbiLQCsa (ORCPT ); Fri, 16 Dec 2022 21:48:30 -0500 Received: from dggsgout11.his.huawei.com (unknown [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68713AE75; Fri, 16 Dec 2022 18:48:29 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4NYr4l71swz4f3kpD; Sat, 17 Dec 2022 10:48:23 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP4 (Coremail) with SMTP id gCh0CgB3m9j5LZ1jmxh7CQ--.11469S5; Sat, 17 Dec 2022 10:48:26 +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 1/4] block/rq_qos: protect 'q->rq_qos' with queue_lock in rq_qos_exit() Date: Sat, 17 Dec 2022 11:09:05 +0800 Message-Id: <20221217030908.1261787-2-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 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: gCh0CgB3m9j5LZ1jmxh7CQ--.11469S5 X-Coremail-Antispam: 1UD129KBjvJXoWxJr4rWrykCFy8WF4DGw1fCrg_yoW8JF4Dpa 4SgrnIkrZ2grn7uan3Gr48Zay3Ga9Ygr48JF4xt393Ar429r129F1vkFy7tayFvF4xArs5 Jrs5Kr95ur1DJ3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jr4l82xGYIkIc2 x26xkF7I0E14v26r1I6r4UM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2 xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v2 6r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2 Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_ Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8Jw CI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUOtC7UUUU U 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 queue_lock is held to protect 'q->rqos' in rq_qos_add() and rq_qos_del(), however, it's not held in rq_qos_exit(), while they can operate the list concurrently: t1 t2 // configure iocost //remove device blk_iocost_init del_gendisk rq_qos_add rq_qos_exit 'rqos->ops->exit' can't be called under spinlock because it might be scheduled out, hence fix the problem by holding queue_lock to fetch the list and reset q->rq_qos first. Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig --- block/blk-rq-qos.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c index 88f0fe7dcf54..efffc6fa55db 100644 --- a/block/blk-rq-qos.c +++ b/block/blk-rq-qos.c @@ -288,9 +288,16 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_da= ta, =20 void rq_qos_exit(struct request_queue *q) { - while (q->rq_qos) { - struct rq_qos *rqos =3D q->rq_qos; - q->rq_qos =3D rqos->next; - rqos->ops->exit(rqos); - } + struct rq_qos *rqos; + + spin_lock_irq(&q->queue_lock); + rqos =3D q->rq_qos; + q->rq_qos =3D NULL; + spin_unlock_irq(&q->queue_lock); + + do { + if (rqos->ops->exit) + rqos->ops->exit(rqos); + rqos =3D rqos->next; + } while (rqos); } --=20 2.31.1