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/
History

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

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2025-10-15T07:58:23.038Z

Updated: 2025-10-15T07:58:23.038Z

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