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

blk-mq: fix blk_mq_tags double free while nr_requests grown

In the case user trigger tags grow by queue sysfs attribute nr_requests,
hctx->sched_tags will be freed directly and replaced with a new
allocated tags, see blk_mq_tag_update_depth().

The problem is that hctx->sched_tags is from elevator->et->tags, while
et->tags is still the freed tags, hence later elevator exit will try to
free the tags again, causing kernel panic.

Fix this problem by replacing et->tags with new allocated tags as well.

Noted there are still some long term problems that will require some
refactor to be fixed thoroughly[1].

[1] https://lore.kernel.org/all/20250815080216.410665-1-yukuai1@huaweicloud.com/

Project Subscriptions

Vendors Products
Linux Kernel Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 01 Dec 2025 06:30:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Mon, 20 Oct 2025 13:30:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Thu, 16 Oct 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate


Wed, 15 Oct 2025 08:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: blk-mq: fix blk_mq_tags double free while nr_requests grown In the case user trigger tags grow by queue sysfs attribute nr_requests, hctx->sched_tags will be freed directly and replaced with a new allocated tags, see blk_mq_tag_update_depth(). The problem is that hctx->sched_tags is from elevator->et->tags, while et->tags is still the freed tags, hence later elevator exit will try to free the tags again, causing kernel panic. Fix this problem by replacing et->tags with new allocated tags as well. Noted there are still some long term problems that will require some refactor to be fixed thoroughly[1]. [1] https://lore.kernel.org/all/20250815080216.410665-1-yukuai1@huaweicloud.com/
Title blk-mq: fix blk_mq_tags double free while nr_requests grown
References

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-01T06:16:11.173Z

Reserved: 2025-04-16T07:20:57.151Z

Link: CVE-2025-39999

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-10-15T08:15:38.210

Modified: 2025-10-16T15:28:59.610

Link: CVE-2025-39999

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-10-15T00:00:00Z

Links: CVE-2025-39999 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-10-20T13:26:57Z

Weaknesses

No weakness.