Commit 8ce9b7c4 authored by Jinke Han's avatar Jinke Han Committed by Jialin Zhang
Browse files

block: don't allow the same type rq_qos add more than once 

mainline inclusion
from mainline-v6.0-rc1
commit 14a6e2eb
category: bugfix
bugzilla: 188088, https://gitee.com/openeuler/kernel/issues/I66GIL
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=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 = q_to_ioc(queue);
if (!ioc) {
        ioc = kzalloc();
					ioc = q_to_ioc(queue);
					if (!ioc) {
						ioc = 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: default avatarJinke Han <hanjinke.666@bytedance.com>
Reviewed-by: default avatarMuchun Song <songmuchun@bytedance.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220720093616.70584-1-hanjinke.666@bytedance.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>

Conflicts:
	block/blk-rq-qos.h
	block/blk-wbt.c

Signed-off-by: default avatarLi Nan <linan122@huawei.com>
Reviewed-by: default avatarHou Tao <houtao1@huawei.com>
parent 60e8843c

block/blk-iocost.c

+13 −7
Original line number Diff line number Diff line
@@ -2874,16 +2874,22 @@ 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 = rq_qos_add(q, rqos);

	if (ret)

		goto err_free_ioc;



	ret = blkcg_activate_policy(q, &blkcg_policy_iocost);

	if (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;

}

	return 0;

}



static struct blkcg_policy_data *ioc_cpd_alloc(gfp_t gfp)

{

block/blk-iolatency.c

+11 −7
Original line number Diff line number Diff line
@@ -772,19 +772,23 @@ int blk_iolatency_init(struct request_queue *q) 
	rqos->ops = &blkcg_iolatency_ops;

	rqos->q = q;



	rq_qos_add(q, rqos);



	ret = rq_qos_add(q, rqos);

	if (ret)

		goto err_free;

	ret = blkcg_activate_policy(q, &blkcg_policy_iolatency);

	if (ret) {

		rq_qos_del(q, rqos);

		kfree(blkiolat);

		return ret;

	}

	if (ret)

		goto err_qos_del;



	timer_setup(&blkiolat->timer, blkiolatency_timer_fn, 0);

	INIT_WORK(&blkiolat->enable_work, blkiolatency_enable_work_fn);



	return 0;



err_qos_del:

	rq_qos_del(q, rqos);

err_free:

	kfree(blkiolat);

	return ret;

}



static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)

block/blk-rq-qos.h

+10 −1
Original line number Diff line number Diff line
@@ -98,7 +98,7 @@ static inline void rq_wait_init(struct rq_wait *rq_wait) 
	init_waitqueue_head(&rq_wait->wait);

}



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
@@ -110,6 +110,8 @@ static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos) 
	blk_mq_freeze_queue(q);



	spin_lock_irq(&q->queue_lock);

	if (rq_qos_id(q, rqos->id))

		goto ebusy;

	rqos->next = q->rq_qos;

	q->rq_qos = rqos;

	spin_unlock_irq(&q->queue_lock);
@@ -118,6 +120,13 @@ static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos) 


	if (rqos->ops->debugfs_attrs)

		blk_mq_debugfs_register_rqos(rqos);



	return 0;

ebusy:

	spin_unlock_irq(&q->queue_lock);

	blk_mq_unfreeze_queue(q);

	return -EBUSY;



}



static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)

block/blk-wbt.c

+11 −1
Original line number Diff line number Diff line
@@ -818,6 +818,7 @@ int wbt_init(struct request_queue *q) 
{

	struct rq_wb *rwb;

	int i;

	int ret;



	rwb = kzalloc(sizeof(*rwb), GFP_KERNEL);

	if (!rwb)
@@ -847,8 +848,17 @@ int wbt_init(struct request_queue *q) 
	/*

	 * Assign rwb and add the stats callback.

	 */

	rq_qos_add(q, &rwb->rqos);

	ret = rq_qos_add(q, &rwb->rqos);

	if (ret)

		goto err_free;



	blk_stat_add_callback(q, rwb->cb);



	return 0;



err_free:

	blk_stat_free_callback(rwb->cb);

	kfree(rwb);

	return ret;



}