{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43404", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.007Z", "datePublished": "2026-05-08T14:21:44.929Z", "dateUpdated": "2026-05-11T22:23:55.638Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T22:23:55.638Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: Fix a hmm_range_fault() livelock / starvation problem\n\nIf hmm_range_fault() fails a folio_trylock() in do_swap_page,\ntrying to acquire the lock of a device-private folio for migration,\nto ram, the function will spin until it succeeds grabbing the lock.\n\nHowever, if the process holding the lock is depending on a work\nitem to be completed, which is scheduled on the same CPU as the\nspinning hmm_range_fault(), that work item might be starved and\nwe end up in a livelock / starvation situation which is never\nresolved.\n\nThis can happen, for example if the process holding the\ndevice-private folio lock is stuck in\n migrate_device_unmap()->lru_add_drain_all()\nsinc lru_add_drain_all() requires a short work-item\nto be run on all online cpus to complete.\n\nA prerequisite for this to happen is:\na) Both zone device and system memory folios are considered in\n migrate_device_unmap(), so that there is a reason to call\n lru_add_drain_all() for a system memory folio while a\n folio lock is held on a zone device folio.\nb) The zone device folio has an initial mapcount > 1 which causes\n at least one migration PTE entry insertion to be deferred to\n try_to_migrate(), which can happen after the call to\n lru_add_drain_all().\nc) No or voluntary only preemption.\n\nThis all seems pretty unlikely to happen, but indeed is hit by\nthe \"xe_exec_system_allocator\" igt test.\n\nResolve this by waiting for the folio to be unlocked if the\nfolio_trylock() fails in do_swap_page().\n\nRename migration_entry_wait_on_locked() to\nsoftleaf_entry_wait_unlock() and update its documentation to\nindicate the new use-case.\n\nFuture code improvements might consider moving\nthe lru_add_drain_all() call in migrate_device_unmap() to be\ncalled *after* all pages have migration entries inserted.\nThat would eliminate also b) above.\n\nv2:\n- Instead of a cond_resched() in hmm_range_fault(),\n eliminate the problem by waiting for the folio to be unlocked\n in do_swap_page() (Alistair Popple, Andrew Morton)\nv3:\n- Add a stub migration_entry_wait_on_locked() for the\n !CONFIG_MIGRATION case. (Kernel Test Robot)\nv4:\n- Rename migrate_entry_wait_on_locked() to\n softleaf_entry_wait_on_locked() and update docs (Alistair Popple)\nv5:\n- Add a WARN_ON_ONCE() for the !CONFIG_MIGRATION\n version of softleaf_entry_wait_on_locked().\n- Modify wording around function names in the commit message\n (Andrew Morton)\n\n(cherry picked from commit a69d1ab971a624c6f112cea61536569d579c3215)" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/migrate.h", "mm/filemap.c", "mm/memory.c", "mm/migrate.c", "mm/migrate_device.c" ], "versions": [ { "version": "1afaeb8293c9addbf4f9140bdd22635fed763459", "lessThan": "94b6d0ba4b640ba23bb6c708a59316e74e5ede63", "status": "affected", "versionType": "git" }, { "version": "1afaeb8293c9addbf4f9140bdd22635fed763459", "lessThan": "7e6e2fc91d4b9b12ec6e137019532568ebcf2680", "status": "affected", "versionType": "git" }, { "version": "1afaeb8293c9addbf4f9140bdd22635fed763459", "lessThan": "b570f37a2ce480be26c665345c5514686a8a0274", "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/migrate.h", "mm/filemap.c", "mm/memory.c", "mm/migrate.c", "mm/migrate_device.c" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.19", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.9", "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": "6.15", "versionEndExcluding": "6.18.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.19.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/94b6d0ba4b640ba23bb6c708a59316e74e5ede63" }, { "url": "https://git.kernel.org/stable/c/7e6e2fc91d4b9b12ec6e137019532568ebcf2680" }, { "url": "https://git.kernel.org/stable/c/b570f37a2ce480be26c665345c5514686a8a0274" } ], "title": "mm: Fix a hmm_range_fault() livelock / starvation problem", "x_generator": { "engine": "bippy-1.2.0" } } } }