From nobody Sat Feb 7 20:51:35 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 27727C00140 for ; Mon, 15 Aug 2022 23:23:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243234AbiHOXXT (ORCPT ); Mon, 15 Aug 2022 19:23:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234174AbiHOXRH (ORCPT ); Mon, 15 Aug 2022 19:17:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FA44149A15; Mon, 15 Aug 2022 13:03:41 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 59A7C612DA; Mon, 15 Aug 2022 20:03:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6259DC433C1; Mon, 15 Aug 2022 20:03:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660593819; bh=AwT3hcAJvFxenTj1NVvhczIFkFp0UrMMz3+/fm3VJqA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CLDQNZUrX6wFUFph7R5/J3kTquN8ReRyi3Kh5aL1Ow2WyRjspaQTmY6bW++Zaz1bA 4FiyUf+BER0Bv38Q8w6EvJnYSCySqrOz7+6+QdMIerCBYiNhgxhxXlRq47n6s6M2ri kNmr3uyAB1ULvEHw8VDdZLNCDQ8FrHlFYKnYniVQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jinke Han , Muchun Song , Tejun Heo , Jens Axboe , Sasha Levin Subject: [PATCH 5.18 1011/1095] block: dont allow the same type rq_qos add more than once Date: Mon, 15 Aug 2022 20:06:50 +0200 Message-Id: <20220815180510.943662166@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180429.240518113@linuxfoundation.org> References: <20220815180429.240518113@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Jinke Han [ Upstream commit 14a6e2eb7df5c7897c15b109cba29ab0c4a791b6 ] In our test of iocost, we encountered some list add/del corruptions of inner_walk list in ioc_timer_fn. The reason can be described as follows: cpu 0 cpu 1 ioc_qos_write ioc_qos_write ioc =3D q_to_ioc(queue); if (!ioc) { ioc =3D kzalloc(); ioc =3D q_to_ioc(queue); if (!ioc) { ioc =3D kzalloc(); ... rq_qos_add(q, rqos); } ... rq_qos_add(q, rqos); ... } When the io.cost.qos file is written by two cpus concurrently, rq_qos may be added to one disk twice. In that case, there will be two iocs enabled and running on one disk. They own different iocgs on their active list. In the ioc_timer_fn function, because of the iocgs from two iocs have the same root iocg, the root iocg's walk_list may be overwritten by each other and this leads to list add/del corruptions in building or destroying the inner_walk list. And so far, the blk-rq-qos framework works in case that one instance for one type rq_qos per queue by default. This patch make this explicit and also fix the crash above. Signed-off-by: Jinke Han Reviewed-by: Muchun Song Acked-by: Tejun Heo Cc: Link: https://lore.kernel.org/r/20220720093616.70584-1-hanjinke.666@bytedan= ce.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-iocost.c | 20 +++++++++++++------- block/blk-iolatency.c | 18 +++++++++++------- block/blk-rq-qos.h | 11 ++++++++++- block/blk-wbt.c | 12 +++++++++++- 4 files changed, 45 insertions(+), 16 deletions(-) diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 16705fbd0699..a19f2db4eeb2 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -2893,15 +2893,21 @@ static int blk_iocost_init(struct request_queue *q) * called before policy activation completion, can't assume that the * target bio has an iocg associated and need to test for NULL iocg. */ - rq_qos_add(q, rqos); + ret =3D rq_qos_add(q, rqos); + if (ret) + goto err_free_ioc; + ret =3D blkcg_activate_policy(q, &blkcg_policy_iocost); - if (ret) { - rq_qos_del(q, rqos); - free_percpu(ioc->pcpu_stat); - kfree(ioc); - return ret; - } + if (ret) + goto err_del_qos; return 0; + +err_del_qos: + rq_qos_del(q, rqos); +err_free_ioc: + free_percpu(ioc->pcpu_stat); + kfree(ioc); + return ret; } =20 static struct blkcg_policy_data *ioc_cpd_alloc(gfp_t gfp) diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index 9568bf8dfe82..7845dca5fcfd 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -773,19 +773,23 @@ int blk_iolatency_init(struct request_queue *q) rqos->ops =3D &blkcg_iolatency_ops; rqos->q =3D q; =20 - rq_qos_add(q, rqos); - + ret =3D rq_qos_add(q, rqos); + if (ret) + goto err_free; ret =3D blkcg_activate_policy(q, &blkcg_policy_iolatency); - if (ret) { - rq_qos_del(q, rqos); - kfree(blkiolat); - return ret; - } + if (ret) + goto err_qos_del; =20 timer_setup(&blkiolat->timer, blkiolatency_timer_fn, 0); INIT_WORK(&blkiolat->enable_work, blkiolatency_enable_work_fn); =20 return 0; + +err_qos_del: + rq_qos_del(q, rqos); +err_free: + kfree(blkiolat); + return ret; } =20 static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val) diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h index 0e46052b018a..08b856570ad1 100644 --- a/block/blk-rq-qos.h +++ b/block/blk-rq-qos.h @@ -86,7 +86,7 @@ static inline void rq_wait_init(struct rq_wait *rq_wait) init_waitqueue_head(&rq_wait->wait); } =20 -static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos) +static inline int rq_qos_add(struct request_queue *q, struct rq_qos *rqos) { /* * No IO can be in-flight when adding rqos, so freeze queue, which @@ -98,6 +98,8 @@ static inline void 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; rqos->next =3D q->rq_qos; q->rq_qos =3D rqos; spin_unlock_irq(&q->queue_lock); @@ -109,6 +111,13 @@ static inline void rq_qos_add(struct request_queue *q,= struct rq_qos *rqos) blk_mq_debugfs_register_rqos(rqos); mutex_unlock(&q->debugfs_mutex); } + + return 0; +ebusy: + spin_unlock_irq(&q->queue_lock); + blk_mq_unfreeze_queue(q); + return -EBUSY; + } =20 static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos) diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 0c119be0e813..ae6ea0b54579 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -820,6 +820,7 @@ int wbt_init(struct request_queue *q) { struct rq_wb *rwb; int i; + int ret; =20 rwb =3D kzalloc(sizeof(*rwb), GFP_KERNEL); if (!rwb) @@ -846,7 +847,10 @@ int wbt_init(struct request_queue *q) /* * Assign rwb and add the stats callback. */ - rq_qos_add(q, &rwb->rqos); + ret =3D rq_qos_add(q, &rwb->rqos); + if (ret) + goto err_free; + blk_stat_add_callback(q, rwb->cb); =20 rwb->min_lat_nsec =3D wbt_default_latency_nsec(q); @@ -855,4 +859,10 @@ int wbt_init(struct request_queue *q) wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags)); =20 return 0; + +err_free: + blk_stat_free_callback(rwb->cb); + kfree(rwb); + return ret; + } --=20 2.35.1