CVE-2026-23097

NameCVE-2026-23097
DescriptionIn 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4475-1, DLA-4476-1, DSA-6126-1, DSA-6127-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.223-1vulnerable
bullseye (security)5.10.249-1fixed
bookworm6.1.159-1vulnerable
bookworm (security)6.1.162-1fixed
trixie6.12.63-1vulnerable
trixie (security)6.12.73-1fixed
forky, sid6.18.12-1fixed
linux-6.1 (PTS)bullseye (security)6.1.162-1~deb11u1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebullseye5.10.249-1DLA-4475-1
linuxsourcebookworm6.1.162-1DSA-6127-1
linuxsourcetrixie6.12.69-1DSA-6126-1
linuxsource(unstable)6.18.8-1
linux-6.1sourcebullseye6.1.162-1~deb11u1DLA-4476-1

Notes

https://git.kernel.org/linus/b7880cb166ab62c2409046b2347261abf701530e (6.19-rc7)

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