FKIE_CVE-2023-53823
Vulnerability from fkie_nvd - Published: 2025-12-09 16:17 - Updated: 2026-08-04 10:19
Severity
Summary
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 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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"block/blk-cgroup.c",
"block/blk-core.c",
"block/blk-rq-qos.c",
"block/blk-wbt.c",
"include/linux/blkdev.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "16398b4638b5cd8c1dc95fc940a1591a801d53ce",
"status": "affected",
"version": "50e34d78815e474d410f342fbe783b18192ca518",
"versionType": "git"
},
{
"lessThan": "a13bd91be22318768d55470cbc0b0f4488ef9edf",
"status": "affected",
"version": "50e34d78815e474d410f342fbe783b18192ca518",
"versionType": "git"
},
{
"status": "affected",
"version": "f28699fafc047ec33299da01e928c3a0073c5cc6",
"versionType": "git"
},
{
"lessThan": "5.19",
"status": "affected",
"version": "5.18.8",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"block/blk-cgroup.c",
"block/blk-core.c",
"block/blk-rq-qos.c",
"block/blk-wbt.c",
"include/linux/blkdev.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.19"
},
{
"lessThan": "5.19",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.4.*",
"status": "unaffected",
"version": "6.4.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.5",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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": "CVE-2023-53823",
"lastModified": "2026-08-04T10:19:22.933",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2025-12-09T16:17:21.107",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/16398b4638b5cd8c1dc95fc940a1591a801d53ce"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a13bd91be22318768d55470cbc0b0f4488ef9edf"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Deferred"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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