Local runtime warnings via false PTE checks
Published Feb 26, 2025 · Updated May 11, 2026
Improper PTE validation in affected Linux kernel revisions allows local users to trigger highmem scheduler runtime warnings. The __kmap_local_sched_in and __kmap_local_sched_out checks apply pte_none to zero-initialized tsk->kmap_ctrl.pteval slots even though a zero PTE is not pte_none on every architecture. Exposure requires CONFIG_DEBUG_KMAP_LOCAL and an architecture such as Xtensa with this PTE behavior; the documented consequence is repeated kernel warnings during scheduling.
Summary
What happened
Improper PTE validation in affected Linux kernel revisions allows local users to trigger highmem scheduler runtime warnings. The __kmap_local_sched_in and __kmap_local_sched_out checks apply pte_none to zero-initialized tsk->kmap_ctrl.pteval slots even though a zero PTE is not pte_none on every architecture. Exposure requires CONFIG_DEBUG_KMAP_LOCAL and an architecture such as Xtensa with this PTE behavior; the documented consequence is repeated kernel warnings during scheduling.
The record
- CVE
- CVE-2022-49081
- Published
- Feb 26, 2025
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 26, 2025CVE publishedPublication date reported by the CVE source.
- May 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=5.11
- Affected versionversion=5fbda3ecd14a5343644979c98d6eb65b7e7de9d8 <66f133ceab7456c789f70a242991ed1b27ba1c3d
- Affected versionversion=5fbda3ecd14a5343644979c98d6eb65b7e7de9d8 <7dd5b3b97716a611fcf67d92fd2370fcb8d50372
- Affected versionversion=5fbda3ecd14a5343644979c98d6eb65b7e7de9d8 <85550b0f5fa5dd3c30469ea702c44444ef242c83
- Affected versionversion=5fbda3ecd14a5343644979c98d6eb65b7e7de9d8 <c21d040de6225414547d9bd31cd200f290991c85
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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