CVE-2023-53823

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

block/rq_qos: protect rq_qos apis with a new lock

commit 50e34d78815e ("block: disable the elevator int del_gendisk")

move rq_qos_exit() from disk_release() to del_gendisk(), this will

introduce some problems:

1) If rq_qos_add() is triggered by enabling iocost/iolatency through

cgroupfs, then it can concurrent with del_gendisk(), it's not safe to

write 'q->rq_qos' concurrently.

2) Activate cgroup policy that is relied on rq_qos will call

rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is

called in the middle, null-ptr-dereference will be triggered in

blkcg_activate_policy().

3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the

disk, then if rq_qos_exit() from del_gendisk() is done before

rq_qos_add(), then memory will be leaked.

This patch add a new disk level mutex 'rq_qos_mutex':

1) The lock will protect rq_qos_exit() directly.

2) For wbt that doesn't re

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References