Block-operation hang via inverted blk-cgroup lock ordering
Published Dec 16, 2025 · Updated Dec 16, 2025
Improper locking in affected Linux kernel releases allows local users to hang block operations via concurrent policy and device changes. blkg_conf_prep calls blk_queue_enter while holding rq_qos_mutex, reversing the freeze-before-mutex order used by queue removal and creating a cycle through sysfs_lock and q_usage_counter. Low-privilege local access to cgroup policy writes and concurrent device removal is required; the reported consequence is an availability-only deadlock.
Summary
What happened
Improper locking in affected Linux kernel releases allows local users to hang block operations via concurrent policy and device changes. blkg_conf_prep calls blk_queue_enter while holding rq_qos_mutex, reversing the freeze-before-mutex order used by queue removal and creating a cycle through sysfs_lock and q_usage_counter. Low-privilege local access to cgroup policy writes and concurrent device removal is required; the reported consequence is an availability-only deadlock.
The record
- CVE
- CVE-2025-68178
- Published
- Dec 16, 2025
- Updated
- Dec 16, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 16, 2025CVE publishedPublication date reported by the CVE source.
- Dec 16, 2025Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0585b24d71197dd9ee8cf79c168a31628c631960
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <56ac639d6fa6fbb99caee74ee1c7276fc9bb47ed
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5d726c4dbeeddef612e6bed27edd29733f4d13af
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e1729523759cda2c0afb76b1c88e0d2f2ef5b7cb
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Technologies
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