{"id":"CVE-2026-89758","revision":"b82b7316f6ba4bfeb241c1e366c1daed","records":[{"revision":"b82b7316f6ba4bfeb241c1e366c1daed","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89758","aliases":[],"title":"mm/mempolicy: skip non-present PMDs when queueing folios","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mempolicy: skip non-present PMDs when queueing folios\n\nPatch series \"mm: handle device-private PMDs in walk callbacks\", v3.\n\nSince commit 368076f52ebe (\"mm/huge_memory: add device-private THP support\nto PMD operations\") a PMD may hold a device-private swap entry whenever an\nHMM-based GPU driver migrates an anonymous THP folio to device memory via\nmigrate_vma_pages().\n\npmd_trans_huge_lock() succeeds for such PMDs (pmd_is_huge() returns true\nfor any non-present, non-none huge PMD), so several MM walk callbacks that\nused to assume present THP or migration entry are now reachable with a\ndevice-private PMD.  The results range from a VM_BUG_ON() firing on debug\nkernels, to an oops on a bogus vmemmap dereference, to silently isolating\nan unrelated live folio from LRU in the aliasing case.\n\n\nThis patch (of 3):\n\nqueue_folios_pmd() is called under pmd_trans_huge_lock(), whose\npmd_is_huge() check returns true for any non-present, non-none PMD\nsoftleaf.  Passing such a PMD to pmd_folio() treats the softleaf encoding\nas a hardware PFN and can return a bogus folio pointer.\n\nMirror queue_folios_pte_range(): handle non-present entries before looking\nup a folio.  Keep migration entries counted as failures, but skip other\nnon-present PMDs such as device-private entries.\n\nPotential trigger: an HMM-based GPU driver migrates an anonymous THP folio\nto device memory via migrate_vma_pages(), leaving a device-private PMD. \nUserspace then calls mbind(), migrate_pages() or set_mempolicy_home_node()\non that range.","state":0,"publishedAt":"2026-09-11T19:47:00.562+00:00","modifiedAt":"2026-10-19T08:52:11.845+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"mm/mempolicy.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"368076f52ebeecd33e10a9f80905d7508b6b6149\",\n                            \"lessThan\": \"3d927093b2add7ced588a926c3dc5d7a83f18596\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"368076f52ebeecd33e10a9f80905d7508b6b6149\",\n                            \"lessThan\": \"2858b4027f491e6fdb8ee2d8923798b619bf2791\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"mm/mempolicy.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.19\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.19\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/3d927093b2add7ced588a926c3dc5d7a83f18596","https://git.kernel.org/stable/c/2858b4027f491e6fdb8ee2d8923798b619bf2791"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89758","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89758","identifiers":["CVE-2026-89758"]},"retained":false,"historicalAffected":[]}],"coverage":[]}