CVE-2022-49778
Estado: AnalizadaMedia (5.5)—
In the Linux kernel, the following vulnerability has been resolved:
arm64/mm: fix incorrect file_map_count for non-leaf pmd/pud
The page table check trigger BUG_ON() unexpectedly when collapse hugepage:
Since pmd_user_accessible_page() doesn't check if a pmd is leaf, it decrease file_map_count for a non-leaf pmd comes from collapse_huge_page(). and so trigger BUG_ON() unexpectedly.
Fix this problem by using pmd_leaf() insteal of pmd_present() in pmd_user_accessible_page(). Moreover, use pud_leaf() for pud_user_accessible_page() too.
Detalles técnicos trazas, registros y código del informe original
------------[ cut here ]------------
kernel BUG at mm/page_table_check.c:82!
Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 6 PID: 68 Comm: khugepaged Not tainted 6.1.0-rc3+ #750
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : page_table_check_clear.isra.0+0x258/0x3f0
lr : page_table_check_clear.isra.0+0x240/0x3f0
[...]
Call trace:
page_table_check_clear.isra.0+0x258/0x3f0
__page_table_check_pmd_clear+0xbc/0x108
pmdp_collapse_flush+0xb0/0x160
collapse_huge_page+0xa08/0x1080
hpage_collapse_scan_pmd+0xf30/0x1590
khugepaged_scan_mm_slot.constprop.0+0x52c/0xac8
khugepaged+0x338/0x518
kthread+0x278/0x2f8
ret_from_fork+0x10/0x20
[...]CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.17%
- Percentil entre todas las CVEs puntuadas: 6
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-617
Referencias
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64/mm: fix incorrect file_map_count for non-leaf pmd/pud\n\nThe page table check trigger BUG_ON() unexpectedly when collapse hugepage:\n\n ------------[ cut here ]------------\n kernel BUG at mm/page_table_check.c:82!\n Internal error: Oops - BUG: 00000000f2000800 [#1] SMP\n Dumping ftrace buffer:\n (ftrace buffer empty)\n Modules linked in:\n CPU: 6 PID: 68 Comm: khugepaged Not tainted 6.1.0-rc3+ #750\n Hardware name: linux,dummy-virt (DT)\n pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n pc : page_table_check_clear.isra.0+0x258/0x3f0\n lr : page_table_check_clear.isra.0+0x240/0x3f0\n[...]\n Call trace:\n page_table_check_clear.isra.0+0x258/0x3f0\n __page_table_check_pmd_clear+0xbc/0x108\n pmdp_collapse_flush+0xb0/0x160\n collapse_huge_page+0xa08/0x1080\n hpage_collapse_scan_pmd+0xf30/0x1590\n khugepaged_scan_mm_slot.constprop.0+0x52c/0xac8\n khugepaged+0x338/0x518\n kthread+0x278/0x2f8\n ret_from_fork+0x10/0x20\n[...]\n\nSince pmd_user_accessible_page() doesn't check if a pmd is leaf, it\ndecrease file_map_count for a non-leaf pmd comes from collapse_huge_page().\nand so trigger BUG_ON() unexpectedly.\n\nFix this problem by using pmd_leaf() insteal of pmd_present() in\npmd_user_accessible_page(). Moreover, use pud_leaf() for\npud_user_accessible_page() too."
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"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: arm64/mm: corrige el file_map_count incorrecto para pmd/pud que no es de hoja. La comprobación de la tabla de páginas se activa inesperadamente BUG_ON() cuando se colapsa hugepage: ------------[ cortar aquí ]------------ ¡ERROR del kernel en mm/page_table_check.c:82! Error interno: Ups - BUG: 00000000f2000800 [#1] SMP Volcando búfer ftrace: (búfer ftrace vacío) Módulos enlazados: CPU: 6 PID: 68 Comm: khugepaged No contaminado 6.1.0-rc3+ #750 Nombre del hardware: linux,dummy-virt (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : page_table_check_clear.isra.0+0x258/0x3f0 lr : page_table_check_clear.isra.0+0x240/0x3f0 [...] Rastreo de llamadas: page_table_check_clear.isra.0+0x258/0x3f0 __page_table_check_pmd_clear+0xbc/0x108 pmdp_collapse_flush+0xb0/0x160 collapse_huge_page+0xa08/0x1080 hpage_collapse_scan_pmd+0xf30/0x1590 khugepaged_scan_mm_slot.constprop.0+0x52c/0xac8 khugepaged+0x338/0x518 kthread+0x278/0x2f8 ret_from_fork+0x10/0x20 [...] Dado que pmd_user_accessible_page() no comprueba si un pmd es hoja, disminuye file_map_count para un pmd que no es hoja que proviene de colapso_huge_page() y, por lo tanto, activa BUG_ON() inesperadamente. Solucione este problema usando pmd_leaf() en lugar de pmd_present() en pmd_user_accessible_page(). Además, use pud_leaf() para pud_user_accessible_page()."
}
],
"lastModified": "2026-06-17T05:19:07.423",
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