fkie_cve-2024-42234
Vulnerability from fkie_nvd
Published
2024-08-07 16:15
Modified
2024-08-08 14:55
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm: fix crashes from deferred split racing folio migration
Even on 6.10-rc6, I've been seeing elusive "Bad page state"s (often on
flags when freeing, yet the flags shown are not bad: PG_locked had been
set and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from
deferred_split_scan()'s folio_put(), and a variety of other BUG and WARN
symptoms implying double free by deferred split and large folio migration.
6.7 commit 9bcef5973e31 ("mm: memcg: fix split queue list crash when large
folio migration") was right to fix the memcg-dependent locking broken in
85ce2c517ade ("memcontrol: only transfer the memcg data for migration"),
but missed a subtlety of deferred_split_scan(): it moves folios to its own
local list to work on them without split_queue_lock, during which time
folio->_deferred_list is not empty, but even the "right" lock does nothing
to secure the folio and the list it is on.
Fortunately, deferred_split_scan() is careful to use folio_try_get(): so
folio_migrate_mapping() can avoid the race by folio_undo_large_rmappable()
while the old folio's reference count is temporarily frozen to 0 - adding
such a freeze in the !mapping case too (originally, folio lock and
unmapping and no swap cache left an anon folio unreachable, so no freezing
was needed there: but the deferred split queue offers a way to reach it).
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * |
{
"configurations": [
{
"nodes": [
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"cpeMatch": [
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "AB2E8DEC-CFD5-4C2B-981D-E7E45A36C352",
"versionEndExcluding": "6.9.10",
"versionStartIncluding": "6.7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
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],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: fix crashes from deferred split racing folio migration\n\nEven on 6.10-rc6, I\u0027ve been seeing elusive \"Bad page state\"s (often on\nflags when freeing, yet the flags shown are not bad: PG_locked had been\nset and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from\ndeferred_split_scan()\u0027s folio_put(), and a variety of other BUG and WARN\nsymptoms implying double free by deferred split and large folio migration.\n\n6.7 commit 9bcef5973e31 (\"mm: memcg: fix split queue list crash when large\nfolio migration\") was right to fix the memcg-dependent locking broken in\n85ce2c517ade (\"memcontrol: only transfer the memcg data for migration\"),\nbut missed a subtlety of deferred_split_scan(): it moves folios to its own\nlocal list to work on them without split_queue_lock, during which time\nfolio-\u003e_deferred_list is not empty, but even the \"right\" lock does nothing\nto secure the folio and the list it is on.\n\nFortunately, deferred_split_scan() is careful to use folio_try_get(): so\nfolio_migrate_mapping() can avoid the race by folio_undo_large_rmappable()\nwhile the old folio\u0027s reference count is temporarily frozen to 0 - adding\nsuch a freeze in the !mapping case too (originally, folio lock and\nunmapping and no swap cache left an anon folio unreachable, so no freezing\nwas needed there: but the deferred split queue offers a way to reach it)."
},
{
"lang": "es",
"value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: mm: corrige fallas debido a la migraci\u00f3n diferida de folios de ejecuciones divididas Incluso en 6.10-rc6, he estado viendo \"estados de p\u00e1gina incorrectos\" esquivos (a menudo en indicadores al liberar, pero los indicadores mostrados no son malos: \u00bfPG_locked se hab\u00eda configurado y borrado?), y VM_BUG_ON_PAGE(page_ref_count(page) == 0)s de folio_put() de deferred_split_scan(), y una variedad de otros s\u00edntomas de ERROR y ADVERTENCIA que implican doble liberaci\u00f3n por divisi\u00f3n diferida y migraci\u00f3n de folios grandes. 6.7 el commit 9bcef5973e31 (\"mm: memcg: corregir el bloqueo de la lista de colas divididas cuando se migra un folio grande\") ten\u00eda raz\u00f3n al corregir el bloqueo dependiente de memcg roto en 85ce2c517ade (\"memcontrol: transferir solo los datos de memcg para la migraci\u00f3n\"), pero omiti\u00f3 una sutileza de deferred_split_scan(): mueve las publicaciones a su propia lista local para trabajar en ellas sin split_queue_lock, tiempo durante el cual folio-\u0026gt;_deferred_list no est\u00e1 vac\u00edo, pero ni siquiera el bloqueo \"derecho\" hace nada para proteger la publicaci\u00f3n y la lista en la que se encuentra. Afortunadamente, deferred_split_scan() tiene cuidado al usar folio_try_get(): por lo que folio_migrate_mapping() puede evitar la ejecuci\u00f3n mediante folio_undo_large_rmappable() mientras el recuento de referencias de la publicaci\u00f3n anterior se congela temporalmente en 0; agregando dicha congelaci\u00f3n tambi\u00e9n en el caso de !mapping (originalmente, El bloqueo y la desasignaci\u00f3n de folios y la falta de cach\u00e9 de intercambio dejaron un folio an\u00f3nimo inalcanzable, por lo que no fue necesario congelarlo all\u00ed: pero la cola dividida diferida ofrece una forma de acceder a \u00e9l)."
}
],
"id": "CVE-2024-42234",
"lastModified": "2024-08-08T14:55:29.913",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2024-08-07T16:15:46.390",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/be9581ea8c058d81154251cb0695987098996cad"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/fc7facce686b64201dbf0b9614cc1d0bfad70010"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-415"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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