mm/huge_memory: fix folio isn't locked in softleaf_to_folio()
In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: fix folio isn't locked in softleaf_to_folio() On arm64 server, we found folio that get from migration entry isn't locked in softleaf_to_folio(). This issue triggers when mTHP splitting and zap_nonpresent_ptes() races, and the root cause is lack of memory barrier in softleaf_to_folio(). The race is as follows: CPU0 CPU1 deferred_split_scan() zap_nonpresent_ptes() lock folio split_folio() unmap_folio() change ptes to migration entries __split_folio_to_order() softleaf_to_folio() set flags(including PG_locked) for tail pages folio = pfn_folio(softleaf_to_pfn(entry)) smp_wmb() VM_WARN_ON_ONCE(!folio_test_locked(folio)) prep_compound_page() for tail pages In __split_folio_to_order(), smp_wmb() guarantees page flags of tail pages are visible before the tail page becomes non-compound. smp_wmb() should be paired with smp_rmb() in softleaf_to_folio(), which is missed. As a result, if zap_nonpresent_ptes() accesses migration entry that stores tail pfn, softleaf_to_folio() may see the updated compound_head of tail page before page->flags. This issue will trigger VM_WARN_ON_ONCE() in pfn_swap_entry_folio() because of the race between folio split and zap_nonpresent_ptes() leading to a folio incorrectly undergoing modification without a folio lock being held. This is a BUG_ON() before commit 93976a20345b ("mm: eliminate further swapops predicates"), which in merged in v6.19-rc1. To fix it, add missing smp_r
CVE-2026-31466
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-2026-31466
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": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "426ee10711586617da869c8bb798214965337617",
"versionType": "git"
},
{
"status": "affected",
"version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd",
"versionType": "git"
},
{
"status": "affected",
"version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "722cfaf6b31d31123439e67b5deac6b1261a3dea",
"versionType": "git"
},
{
"status": "affected",
"version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "7ddcf4a245c1c5a91fdd9698757e3d95179ffe41",
"versionType": "git"
},
{
"status": "affected",
"version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "b8c49ad888892ad7b77062b9c102b799a3e9b4f8",
"versionType": "git"
},
{
"status": "affected",
"version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "7ad1997b9bc8032603df8f091761114479285769",
"versionType": "git"
},
{
"status": "affected",
"version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7",
"versionType": "git"
},
{
"status": "affected",
"version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
"lessThan": "4c5e7f0fcd592801c9cc18f29f80fbee84eb8669",
"versionType": "git"
}
],
"programFiles": [
"include/linux/leafops.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.5"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.5",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.253",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.168",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.134",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.81",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.21",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.11",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/linux/leafops.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31466
Source reference:
/cveMetadata/cveId
Publisher severity
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- Event
- #28282 · Revision 1
- Added to Heist Feed
- Publisher date