CVE-2025-22015 (GCVE-0-2025-22015)
Vulnerability from cvelistv5
Published
2025-04-08 08:18
Modified
2026-08-05 11:56
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/migrate: fix shmem xarray update during migration A shmem folio can be either in page cache or in swap cache, but not at the same time. Namely, once it is in swap cache, folio->mapping should be NULL, and the folio is no longer in a shmem mapping. In __folio_migrate_mapping(), to determine the number of xarray entries to update, folio_test_swapbacked() is used, but that conflates shmem in page cache case and shmem in swap cache case. It leads to xarray multi-index entry corruption, since it turns a sibling entry to a normal entry during xas_store() (see [1] for a userspace reproduction). Fix it by only using folio_test_swapcache() to determine whether xarray is storing swap cache entries or not to choose the right number of xarray entries to update. [1] https://lore.kernel.org/linux-mm/Z8idPCkaJW1IChjT@casper.infradead.org/ Note: In __split_huge_page(), folio_test_anon() && folio_test_swapcache() is used to get swap_cache address space, but that ignores the shmem folio in swap cache case. It could lead to NULL pointer dereferencing when a in-swap-cache shmem folio is split at __xa_store(), since !folio_test_anon() is true and folio->mapping is NULL. But fortunately, its caller split_huge_page_to_list_to_order() bails out early with EBUSY when folio->mapping is NULL. So no need to take care of it here.
References
Impacted products
Vendor Product Version
Linux Linux Version: be72d197b2281e2ee3f28017fc9be1ab17e26d16
Version: 07550b1461d4d0499165e7d6f7718cfd0e440427
Version: fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c
Version: fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c
Version: fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c
Version: 6.1.71   ≤
Version: 6.6.10   ≤
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