From nobody Wed Sep 17 15:46:54 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 From nobody Wed Sep 17 15:46:54 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 69DB5C4332F for ; Sat, 17 Dec 2022 02:48:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230228AbiLQCsr (ORCPT ); Fri, 16 Dec 2022 21:48:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230181AbiLQCsa (ORCPT ); Fri, 16 Dec 2022 21:48:30 -0500 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D70AFB1E5; Fri, 16 Dec 2022 18:48:29 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4NYr4m1k4gz4f3npg; Sat, 17 Dec 2022 10:48:24 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP4 (Coremail) with SMTP id gCh0CgB3m9j5LZ1jmxh7CQ--.11469S6; Sat, 17 Dec 2022 10:48:27 +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 2/4] block/rq_qos: fail rq_qos_add() after del_gendisk() Date: Sat, 17 Dec 2022 11:09:06 +0800 Message-Id: <20221217030908.1261787-3-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--.11469S6 X-Coremail-Antispam: 1UD129KBjvJXoW7CF15XrWkCF15trWxGr1ftFb_yoW8CrW7pa 1xKr13Aayvgrs7WaykGw4rXasxC34rKryfCFWxWrWSvF4j9F1j9F10yFWUWayrZFZ3AF4f Xr4rAr95Cr48GwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2 xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v2 6r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2 Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_ Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8Jw CI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUe1v3UUUU 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 rq_qos_add() can still succeed after rq_qos_exit() is done, which will cause memory leak because such rq_qos will never be removed. t1 t2 // configure iocost blk_iocost_init //remove device del_gendisk rq_qos_exit // done nothing because rq_qos doesn't exist rq_qos_add // will succeed, and rq_qos won't be removed rq_qos_add() will also be called from blkcg_init_disk() from __alloc_disk_node(), and GD_DEAD can distinguish between disk allocation and disk deletion. Fix the problem by checking GD_DEAD in rq_qos_add(). Signed-off-by: Yu Kuai --- block/blk-rq-qos.h | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h index 1ef1f7d4bc3c..81e087139ffb 100644 --- a/block/blk-rq-qos.h +++ b/block/blk-rq-qos.h @@ -87,6 +87,7 @@ static inline void rq_wait_init(struct rq_wait *rq_wait) =20 static inline int rq_qos_add(struct request_queue *q, struct rq_qos *rqos) { + int err; /* * No IO can be in-flight when adding rqos, so freeze queue, which * is fine since we only support rq_qos for blk-mq queue. @@ -97,8 +98,16 @@ static inline int rq_qos_add(struct request_queue *q, st= ruct rq_qos *rqos) blk_mq_freeze_queue(q); =20 spin_lock_irq(&q->queue_lock); - if (rq_qos_id(q, rqos->id)) - goto ebusy; + if (rq_qos_id(q, rqos->id)) { + err =3D -EBUSY; + goto err; + } + + if (q->disk && test_bit(GD_DEAD, &q->disk->state)) { + err =3D -ENODEV; + goto err; + } + rqos->next =3D q->rq_qos; q->rq_qos =3D rqos; spin_unlock_irq(&q->queue_lock); @@ -112,10 +121,10 @@ static inline int rq_qos_add(struct request_queue *q,= struct rq_qos *rqos) } =20 return 0; -ebusy: +err: spin_unlock_irq(&q->queue_lock); blk_mq_unfreeze_queue(q); - return -EBUSY; + return err; =20 } =20 --=20 2.31.1 From nobody Wed Sep 17 15:46:54 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 4A7A5C4332F for ; Sat, 17 Dec 2022 02:49:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230247AbiLQCs5 (ORCPT ); Fri, 16 Dec 2022 21:48:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230195AbiLQCsb (ORCPT ); Fri, 16 Dec 2022 21:48:31 -0500 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 514F8A1BA; Fri, 16 Dec 2022 18:48:30 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4NYr4m4v90z4f3nqH; Sat, 17 Dec 2022 10:48:24 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.127.227]) by APP4 (Coremail) with SMTP id gCh0CgB3m9j5LZ1jmxh7CQ--.11469S7; Sat, 17 Dec 2022 10:48:27 +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 3/4] blk-cgroup: add a new interface blkcg_conf_close_bdev() Date: Sat, 17 Dec 2022 11:09:07 +0800 Message-Id: <20221217030908.1261787-4-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--.11469S7 X-Coremail-Antispam: 1UD129KBjvJXoWxCr1rGr1kAry7WFyfJr43KFg_yoW5CFW3pF W5tay3Jry2grn0vFsF9ay2gr1Fyr4kKFyfJ393GryYkrWIgw1xZF1kZF1kKrWrXFZ3Ars8 ZFWSvrWjkr18CrJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26ryj6s0DM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j6F4UJw A2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2 xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v2 6r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2 Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUCVW8JwCI42IY6xIIjxv20xvEc7CjxVAFwI0_ Cr0_Gr1UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8Jw CI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUFfHUDUUU 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 It's the same as blkdev_put_no_open() for now, prepare to synchronize del_gendisk() with configuring cgroup policy. There are no functional changes. Signed-off-by: Yu Kuai --- block/blk-cgroup.c | 9 +++++++-- block/blk-cgroup.h | 1 + block/blk-iocost.c | 8 ++++---- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 77f44472b41e..ad612148cf3b 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -662,6 +662,11 @@ struct block_device *blkcg_conf_open_bdev(char **input= p) return bdev; } =20 +void blkcg_conf_close_bdev(struct block_device *bdev) +{ + blkdev_put_no_open(bdev); +} + /** * blkg_conf_prep - parse and prepare for per-blkg config update * @blkcg: target block cgroup @@ -781,7 +786,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct bl= kcg_policy *pol, fail_exit_queue: blk_queue_exit(q); fail: - blkdev_put_no_open(bdev); + blkcg_conf_close_bdev(bdev); /* * If queue was bypassing, we should retry. Do so after a * short msleep(). It isn't strictly necessary but queue @@ -808,7 +813,7 @@ void blkg_conf_finish(struct blkg_conf_ctx *ctx) { spin_unlock_irq(&bdev_get_queue(ctx->bdev)->queue_lock); rcu_read_unlock(); - blkdev_put_no_open(ctx->bdev); + blkcg_conf_close_bdev(ctx->bdev); } EXPORT_SYMBOL_GPL(blkg_conf_finish); =20 diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 1e94e404eaa8..d4ae1e7288c1 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -214,6 +214,7 @@ struct blkg_conf_ctx { }; =20 struct block_device *blkcg_conf_open_bdev(char **inputp); +void blkcg_conf_close_bdev(struct block_device *bdev); int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, char *input, struct blkg_conf_ctx *ctx); void blkg_conf_finish(struct blkg_conf_ctx *ctx); diff --git a/block/blk-iocost.c b/block/blk-iocost.c index d1bdc12deaa7..5294a404c892 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -3288,7 +3288,7 @@ static ssize_t ioc_qos_write(struct kernfs_open_file = *of, char *input, blk_mq_unquiesce_queue(disk->queue); blk_mq_unfreeze_queue(disk->queue); =20 - blkdev_put_no_open(bdev); + blkcg_conf_close_bdev(bdev); return nbytes; einval: spin_unlock_irq(&ioc->lock); @@ -3298,7 +3298,7 @@ static ssize_t ioc_qos_write(struct kernfs_open_file = *of, char *input, =20 ret =3D -EINVAL; err: - blkdev_put_no_open(bdev); + blkcg_conf_close_bdev(bdev); return ret; } =20 @@ -3424,7 +3424,7 @@ static ssize_t ioc_cost_model_write(struct kernfs_ope= n_file *of, char *input, blk_mq_unquiesce_queue(q); blk_mq_unfreeze_queue(q); =20 - blkdev_put_no_open(bdev); + blkcg_conf_close_bdev(bdev); return nbytes; =20 einval: @@ -3435,7 +3435,7 @@ static ssize_t ioc_cost_model_write(struct kernfs_ope= n_file *of, char *input, =20 ret =3D -EINVAL; err: - blkdev_put_no_open(bdev); + blkcg_conf_close_bdev(bdev); return ret; } =20 --=20 2.31.1 From nobody Wed Sep 17 15:46:54 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 79C57C4167B for ; Sat, 17 Dec 2022 02:49:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230265AbiLQCtA (ORCPT ); Fri, 16 Dec 2022 21:49:00 -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 Content-Transfer-Encoding: quoted-printable 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-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 =3D 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 **inpu= tp) return ERR_PTR(-ENODEV); } =20 + mutex_lock(&bdev->bd_queue->blkcg_pols_lock); *inputp =3D input; return bdev; } =20 void blkcg_conf_close_bdev(struct block_device *bdev) { + mutex_unlock(&bdev->bd_queue->blkcg_pols_lock); blkdev_put_no_open(bdev); } =20 @@ -1277,6 +1279,7 @@ int blkcg_init_disk(struct gendisk *disk) int ret; =20 INIT_LIST_HEAD(&q->blkg_list); + mutex_init(&q->blkcg_pols_lock); =20 new_blkg =3D 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; =20 +#ifdef CONFIG_BLK_CGROUP + mutex_lock(&q->blkcg_pols_lock); +#endif + spin_lock_irq(&q->queue_lock); rqos =3D q->rq_qos; q->rq_qos =3D NULL; @@ -300,4 +304,8 @@ void rq_qos_exit(struct request_queue *q) rqos->ops->exit(rqos); rqos =3D 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 =20 struct queue_limits limits; --=20 2.31.1