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CVE-2025-68780

Estado: AplazadaSin puntuar—

In the Linux kernel, the following vulnerability has been resolved:

sched/deadline: only set free_cpus for online runqueues

Commit 16b269436b72 ("sched/deadline: Modify cpudl::free_cpus to reflect rd->online") introduced the cpudl_set/clear_freecpu functions to allow the cpu_dl::free_cpus mask to be manipulated by the deadline scheduler class rq_on/offline callbacks so the mask would also reflect this state.

Commit 9659e1eeee28 ("sched/deadline: Remove cpu_active_mask from cpudl_find()") removed the check of the cpu_active_mask to save some processing on the premise that the cpudl::free_cpus mask already reflected the runqueue online state.

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Unfortunately, there are cases where it is possible for the cpudl_clear function to set the free_cpus bit for a CPU when the deadline runqueue is offline. When this occurs while a CPU is connected to the default root domain the flag may retain the bad state after the CPU has been unplugged. Later, a different CPU that is transitioning through the default root domain may push a deadline task to the powered down CPU when cpudl_find sees its free_cpus bit is set. If this happens the task will not have the opportunity to run.

One example is outlined here: https://lore.kernel.org/lkml/20250110233010.2339521-1-opendmb@gmail.com

Another occurs when the last deadline task is migrated from a CPU that has an offlined runqueue. The dequeue_task member of the deadline scheduler class will eventually call cpudl_clear and set the free_cpus bit for the CPU.

This commit modifies the cpudl_clear function to be aware of the online state of the deadline runqueue so that the free_cpus mask can be updated appropriately.

It is no longer necessary to manage the mask outside of the cpudl_set/clear functions so the cpudl_set/clear_freecpu functions are removed. In addition, since the free_cpus mask is now only updated under the cpudl lock the code was changed to use the non-atomic __cpumask functions.

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

Probabilidad de explotación (EPSS)

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)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2025-68780",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "9659e1eeee28f7025b6545934d644d19e9c6e603",
              "lessThan": "9019e399684e3cc68c4a3f050e268f74d69c1317",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9659e1eeee28f7025b6545934d644d19e9c6e603",
              "lessThan": "fb36846cbcc936954f2ad2bffdff13d16c0be08a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9659e1eeee28f7025b6545934d644d19e9c6e603",
              "lessThan": "91e448e69aca4bb0ba2e998eb3e555644db7322b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9659e1eeee28f7025b6545934d644d19e9c6e603",
              "lessThan": "dbc61834b0412435df21c71410562d933e4eba49",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9659e1eeee28f7025b6545934d644d19e9c6e603",
              "lessThan": "3ed049fbfb4d75b4e0b8ab54c934f485129d5dc8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9659e1eeee28f7025b6545934d644d19e9c6e603",
              "lessThan": "382748c05e58a9f1935f5a653c352422375566ea",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "kernel/sched/cpudeadline.c",
            "kernel/sched/cpudeadline.h",
            "kernel/sched/deadline.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.15.198",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.160",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.120",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.64",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "kernel/sched/cpudeadline.c",
            "kernel/sched/cpudeadline.h",
            "kernel/sched/deadline.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-01-13T16:15:57.657",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/382748c05e58a9f1935f5a653c352422375566ea",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3ed049fbfb4d75b4e0b8ab54c934f485129d5dc8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9019e399684e3cc68c4a3f050e268f74d69c1317",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/91e448e69aca4bb0ba2e998eb3e555644db7322b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dbc61834b0412435df21c71410562d933e4eba49",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fb36846cbcc936954f2ad2bffdff13d16c0be08a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/deadline: only set free_cpus for online runqueues\n\nCommit 16b269436b72 (\"sched/deadline: Modify cpudl::free_cpus\nto reflect rd->online\") introduced the cpudl_set/clear_freecpu\nfunctions to allow the cpu_dl::free_cpus mask to be manipulated\nby the deadline scheduler class rq_on/offline callbacks so the\nmask would also reflect this state.\n\nCommit 9659e1eeee28 (\"sched/deadline: Remove cpu_active_mask\nfrom cpudl_find()\") removed the check of the cpu_active_mask to\nsave some processing on the premise that the cpudl::free_cpus\nmask already reflected the runqueue online state.\n\nUnfortunately, there are cases where it is possible for the\ncpudl_clear function to set the free_cpus bit for a CPU when the\ndeadline runqueue is offline. When this occurs while a CPU is\nconnected to the default root domain the flag may retain the bad\nstate after the CPU has been unplugged. Later, a different CPU\nthat is transitioning through the default root domain may push a\ndeadline task to the powered down CPU when cpudl_find sees its\nfree_cpus bit is set. If this happens the task will not have the\nopportunity to run.\n\nOne example is outlined here:\nhttps://lore.kernel.org/lkml/20250110233010.2339521-1-opendmb@gmail.com\n\nAnother occurs when the last deadline task is migrated from a\nCPU that has an offlined runqueue. The dequeue_task member of\nthe deadline scheduler class will eventually call cpudl_clear\nand set the free_cpus bit for the CPU.\n\nThis commit modifies the cpudl_clear function to be aware of the\nonline state of the deadline runqueue so that the free_cpus mask\ncan be updated appropriately.\n\nIt is no longer necessary to manage the mask outside of the\ncpudl_set/clear functions so the cpudl_set/clear_freecpu\nfunctions are removed. In addition, since the free_cpus mask is\nnow only updated under the cpudl lock the code was changed to\nuse the non-atomic __cpumask functions."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nsched/deadline: solo establecer free_cpus para runqueues en línea\n\nEl commit 16b269436b72 ('sched/deadline: Modificar cpudl::free_cpus para reflejar rd->online') introdujo las funciones cpudl_set/clear_freecpu para permitir que la máscara cpu_dl::free_cpus fuera manipulada por las devoluciones de llamada rq_on/offline de la clase de planificador de plazo para que la máscara también reflejara este estado.\n\nEl commit 9659e1eeee28 ('sched/deadline: Eliminar cpu_active_mask de cpudl_find()') eliminó la comprobación de la cpu_active_mask para ahorrar algo de procesamiento bajo la premisa de que la máscara cpudl::free_cpus ya reflejaba el estado en línea del runqueue.\n\nDesafortunadamente, hay casos en los que es posible que la función cpudl_clear establezca el bit free_cpus para una CPU cuando el runqueue de plazo está fuera de línea. Cuando esto ocurre mientras una CPU está conectada al dominio raíz predeterminado, el indicador puede retener el estado incorrecto después de que la CPU haya sido desconectada. Más tarde, una CPU diferente que está en transición a través del dominio raíz predeterminado puede empujar una tarea de plazo a la CPU apagada cuando cpudl_find ve que su bit free_cpus está establecido. Si esto sucede, la tarea no tendrá la oportunidad de ejecutarse.\n\nUn ejemplo se describe aquí:\nhttps://lore.kernel.org/lkml/20250110233010.2339521-1-opendmb@gmail.com\n\nOtro ocurre cuando la última tarea de plazo es migrada de una CPU que tiene un runqueue fuera de línea. El miembro dequeue_task de la clase de planificador de plazo eventualmente llamará a cpudl_clear y establecerá el bit free_cpus para la CPU.\n\nEste commit modifica la función cpudl_clear para que sea consciente del estado en línea del runqueue de plazo para que la máscara free_cpus pueda ser actualizada apropiadamente.\n\nYa no es necesario gestionar la máscara fuera de las funciones cpudl_set/clear, por lo que las funciones cpudl_set/clear_freecpu son eliminadas. Además, dado que la máscara free_cpus ahora solo se actualiza bajo el bloqueo cpudl, el código fue cambiado para usar las funciones no atómicas __cpumask."
    }
  ],
  "lastModified": "2026-06-17T09:59:34.603",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}