mm/migrate: fix shmem xarray update during migration
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.
CVE-2025-22015
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2025-22015
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "be72d197b2281e2ee3f28017fc9be1ab17e26d16",
"lessThan": "49100c0b070e900f87c8fac3be9b9ef8a30fa673",
"versionType": "git"
},
{
"status": "affected",
"version": "07550b1461d4d0499165e7d6f7718cfd0e440427",
"lessThan": "29124ae980e2860f0eec7355949d3d3292ee81da",
"versionType": "git"
},
{
"status": "affected",
"version": "fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c",
"lessThan": "c057ee03f751d6cecf7ee64f52f6545d94082aaa",
"versionType": "git"
},
{
"status": "affected",
"version": "fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c",
"lessThan": "75cfb92eb63298d717b6b0118f91ba12c4fcfeb5",
"versionType": "git"
},
{
"status": "affected",
"version": "fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c",
"lessThan": "60cf233b585cdf1f3c5e52d1225606b86acd08b0",
"versionType": "git"
},
{
"status": "affected",
"version": "6.1.71",
"lessThan": "6.1.132",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.10",
"lessThan": "6.6.85",
"versionType": "semver"
}
],
"programFiles": [
"mm/migrate.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.7"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.7",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.132",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.85",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.21",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.13.9",
"versionType": "semver",
"lessThanOrEqual": "6.13.*"
},
{
"status": "unaffected",
"version": "6.14",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"mm/migrate.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-22015
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #30452 · Revision 1
- Added to Heist Feed
- Publisher date