GHSA-H5MG-VW9M-F6V8
Vulnerability from github – Published: 2025-12-09 18:30 – Updated: 2025-12-09 18:30In 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 relied on blk-cgroup, rq_qos_add() can only be called from disk initialization for now because wbt can't be destructed until rq_qos_exit(), so it's safe not to protect wbt for now. Hoever, in case that rq_qos dynamically destruction is supported in the furture, this patch also protect rq_qos_add() from wbt_init() directly, this is enough because blk-sysfs already synchronize writers with disk removal.
3) For iocost and iolatency, in order to synchronize disk removal and cgroup configuration, the lock is held after blkdev_get_no_open() from blkg_conf_open_bdev(), and is released in blkg_conf_exit(). In order to fix the above memory leak, disk_live() is checked after holding the new lock.
{
"affected": [],
"aliases": [
"CVE-2023-53823"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-09T16:17:21Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock/rq_qos: protect rq_qos apis with a new lock\n\ncommit 50e34d78815e (\"block: disable the elevator int del_gendisk\")\nmove rq_qos_exit() from disk_release() to del_gendisk(), this will\nintroduce some problems:\n\n1) If rq_qos_add() is triggered by enabling iocost/iolatency through\n cgroupfs, then it can concurrent with del_gendisk(), it\u0027s not safe to\n write \u0027q-\u003erq_qos\u0027 concurrently.\n\n2) Activate cgroup policy that is relied on rq_qos will call\n rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is\n called in the middle, null-ptr-dereference will be triggered in\n blkcg_activate_policy().\n\n3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the\n disk, then if rq_qos_exit() from del_gendisk() is done before\n rq_qos_add(), then memory will be leaked.\n\nThis patch add a new disk level mutex \u0027rq_qos_mutex\u0027:\n\n1) The lock will protect rq_qos_exit() directly.\n\n2) For wbt that doesn\u0027t relied on blk-cgroup, rq_qos_add() can only be\n called from disk initialization for now because wbt can\u0027t be\n destructed until rq_qos_exit(), so it\u0027s safe not to protect wbt for\n now. Hoever, in case that rq_qos dynamically destruction is supported\n in the furture, this patch also protect rq_qos_add() from wbt_init()\n directly, this is enough because blk-sysfs already synchronize\n writers with disk removal.\n\n3) For iocost and iolatency, in order to synchronize disk removal and\n cgroup configuration, the lock is held after blkdev_get_no_open()\n from blkg_conf_open_bdev(), and is released in blkg_conf_exit().\n In order to fix the above memory leak, disk_live() is checked after\n holding the new lock.",
"id": "GHSA-h5mg-vw9m-f6v8",
"modified": "2025-12-09T18:30:32Z",
"published": "2025-12-09T18:30:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53823"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/16398b4638b5cd8c1dc95fc940a1591a801d53ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a13bd91be22318768d55470cbc0b0f4488ef9edf"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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