{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31466","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-03-09T15:48:24.097Z","datePublished":"2026-04-22T13:53:56.259Z","dateUpdated":"2026-05-11T22:09:16.806Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T22:09:16.806Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/huge_memory: fix folio isn't locked in softleaf_to_folio()\n\nOn arm64 server, we found folio that get from migration entry isn't locked\nin softleaf_to_folio().  This issue triggers when mTHP splitting and\nzap_nonpresent_ptes() races, and the root cause is lack of memory barrier\nin softleaf_to_folio().  The race is as follows:\n\n\tCPU0                                             CPU1\n\ndeferred_split_scan()                              zap_nonpresent_ptes()\n  lock folio\n  split_folio()\n    unmap_folio()\n      change ptes to migration entries\n    __split_folio_to_order()                         softleaf_to_folio()\n      set flags(including PG_locked) for tail pages    folio = pfn_folio(softleaf_to_pfn(entry))\n      smp_wmb()                                        VM_WARN_ON_ONCE(!folio_test_locked(folio))\n      prep_compound_page() for tail pages\n\nIn __split_folio_to_order(), smp_wmb() guarantees page flags of tail pages\nare visible before the tail page becomes non-compound.  smp_wmb() should\nbe paired with smp_rmb() in softleaf_to_folio(), which is missed.  As a\nresult, if zap_nonpresent_ptes() accesses migration entry that stores tail\npfn, softleaf_to_folio() may see the updated compound_head of tail page\nbefore page->flags.\n\nThis issue will trigger VM_WARN_ON_ONCE() in pfn_swap_entry_folio()\nbecause of the race between folio split and zap_nonpresent_ptes()\nleading to a folio incorrectly undergoing modification without a folio\nlock being held.\n\nThis is a BUG_ON() before commit 93976a20345b (\"mm: eliminate further\nswapops predicates\"), which in merged in v6.19-rc1.\n\nTo fix it, add missing smp_rmb() if the softleaf entry is migration entry\nin softleaf_to_folio() and softleaf_to_page().\n\n[tujinjiang@huawei.com: update function name and comments]"}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/leafops.h"],"versions":[{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"426ee10711586617da869c8bb798214965337617","status":"affected","versionType":"git"},{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd","status":"affected","versionType":"git"},{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"722cfaf6b31d31123439e67b5deac6b1261a3dea","status":"affected","versionType":"git"},{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"7ddcf4a245c1c5a91fdd9698757e3d95179ffe41","status":"affected","versionType":"git"},{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"b8c49ad888892ad7b77062b9c102b799a3e9b4f8","status":"affected","versionType":"git"},{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"7ad1997b9bc8032603df8f091761114479285769","status":"affected","versionType":"git"},{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7","status":"affected","versionType":"git"},{"version":"e9b61f19858a5d6c42ce2298cf138279375d0d9b","lessThan":"4c5e7f0fcd592801c9cc18f29f80fbee84eb8669","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/leafops.h"],"versions":[{"version":"4.5","status":"affected"},{"version":"0","lessThan":"4.5","status":"unaffected","versionType":"semver"},{"version":"5.10.253","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.203","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.168","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.134","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.81","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.21","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"6.19.11","lessThanOrEqual":"6.19.*","status":"unaffected","versionType":"semver"},{"version":"7.0","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"5.10.253"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.1.168"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.6.134"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.12.81"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.18.21"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.19.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"7.0"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/426ee10711586617da869c8bb798214965337617"},{"url":"https://git.kernel.org/stable/c/f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd"},{"url":"https://git.kernel.org/stable/c/722cfaf6b31d31123439e67b5deac6b1261a3dea"},{"url":"https://git.kernel.org/stable/c/7ddcf4a245c1c5a91fdd9698757e3d95179ffe41"},{"url":"https://git.kernel.org/stable/c/b8c49ad888892ad7b77062b9c102b799a3e9b4f8"},{"url":"https://git.kernel.org/stable/c/7ad1997b9bc8032603df8f091761114479285769"},{"url":"https://git.kernel.org/stable/c/8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7"},{"url":"https://git.kernel.org/stable/c/4c5e7f0fcd592801c9cc18f29f80fbee84eb8669"}],"title":"mm/huge_memory: fix folio isn't locked in softleaf_to_folio()","x_generator":{"engine":"bippy-1.2.0"}}}}