{"id":"CVE-2026-93217","summary":"mm/madvise: skip device-private PMDs in cold and pageout walks","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/madvise: skip device-private PMDs in cold and pageout walks\n\nmadvise_cold_or_pageout_pte_range() takes pmd_trans_huge_lock(), whose\npmd_is_huge() check returns true for a device-private PMD.  The subsequent\n!pmd_present() branch has a VM_BUG_ON() asserting migration is the only\nallowed non-present case; a device-private PMD trips it.\n\nSkip device-private PMDs in that non-present branch and continue to\nhuge_unlock before calling pmd_folio().  Downgrade the check to\nVM_WARN_ON_ONCE() so an unexpected PMD softleaf logs a warning rather than\npanicking.  Drop the thp_migration_supported() guard: it expands to\nIS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both\npmd_is_migration_entry() and pmd_is_device_private_entry() already return\nfalse when that config is not selected, so the guard suppresses only the\ncase where the warning would already be silent.\n\nPotential trigger: an HMM-based GPU driver races with\nmadvise(MADV_COLD)/MADV_PAGEOUT: pmd_trans_huge(*pmd) reads true, then\nmigrate_vma_pages() flips the PMD to a device-private entry before the PMD\nlock is acquired.","modified":"2026-09-26T03:48:34.697313891Z","published":"2026-09-24T15:10:40.487Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93217.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5c0d7b658cda62cd17cb3652783386d5608030ef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d4b76d0b03cb49611312ecc4bcfb55ccdf0843e2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93217.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93217"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"368076f52ebeecd33e10a9f80905d7508b6b6149"},{"fixed":"5c0d7b658cda62cd17cb3652783386d5608030ef"},{"fixed":"d4b76d0b03cb49611312ecc4bcfb55ccdf0843e2"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93217.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93217.json"}}],"schema_version":"1.9.0"}