FKIE_CVE-2026-23012

Vulnerability from fkie_nvd - Published: 2026-01-25 15:15 - Updated: 2026-01-26 15:03
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: remove call_control in inactive contexts If damon_call() is executed against a DAMON context that is not running, the function returns error while keeping the damon_call_control object linked to the context's call_controls list. Let's suppose the object is deallocated after the damon_call(), and yet another damon_call() is executed against the same context. The function tries to add the new damon_call_control object to the call_controls list, which still has the pointer to the previous damon_call_control object, which is deallocated. As a result, use-after-free happens. This can actually be triggered using the DAMON sysfs interface. It is not easily exploitable since it requires the sysfs write permission and making a definitely weird file writes, though. Please refer to the report for more details about the issue reproduction steps. Fix the issue by making two changes. Firstly, move the final kdamond_call() for cancelling all existing damon_call() requests from terminating DAMON context to be done before the ctx->kdamond reset. This makes any code that sees NULL ctx->kdamond can safely assume the context may not access damon_call() requests anymore. Secondly, let damon_call() to cleanup the damon_call_control objects that were added to the already-terminated DAMON context, before returning the error.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/23b061f421eef03647b512f3df48861706c87db3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f9132fbc2e83baf2c45a77043672a63a675c9394
Impacted products
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/core: remove call_control in inactive contexts\n\nIf damon_call() is executed against a DAMON context that is not running,\nthe function returns error while keeping the damon_call_control object\nlinked to the context\u0027s call_controls list.  Let\u0027s suppose the object is\ndeallocated after the damon_call(), and yet another damon_call() is\nexecuted against the same context.  The function tries to add the new\ndamon_call_control object to the call_controls list, which still has the\npointer to the previous damon_call_control object, which is deallocated. \nAs a result, use-after-free happens.\n\nThis can actually be triggered using the DAMON sysfs interface.  It is not\neasily exploitable since it requires the sysfs write permission and making\na definitely weird file writes, though.  Please refer to the report for\nmore details about the issue reproduction steps.\n\nFix the issue by making two changes.  Firstly, move the final\nkdamond_call() for cancelling all existing damon_call() requests from\nterminating DAMON context to be done before the ctx-\u003ekdamond reset.  This\nmakes any code that sees NULL ctx-\u003ekdamond can safely assume the context\nmay not access damon_call() requests anymore.  Secondly, let damon_call()\nto cleanup the damon_call_control objects that were added to the\nalready-terminated DAMON context, before returning the error."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nmm/damon/core: eliminar call_control en contextos inactivos\n\nSi damon_call() se ejecuta contra un contexto DAMON que no est\u00e1 en ejecuci\u00f3n, la funci\u00f3n devuelve un error mientras mantiene el objeto damon_call_control vinculado a la lista call_controls del contexto. Supongamos que el objeto es desasignado despu\u00e9s de damon_call(), y se ejecuta otro damon_call() contra el mismo contexto. La funci\u00f3n intenta a\u00f1adir el nuevo objeto damon_call_control a la lista call_controls, que todav\u00eda tiene el puntero al objeto damon_call_control anterior, que est\u00e1 desasignado. Como resultado, ocurre un uso despu\u00e9s de liberaci\u00f3n.\n\nEsto puede ser realmente activado usando la interfaz sysfs de DAMON. Sin embargo, no es f\u00e1cilmente explotable ya que requiere el permiso de escritura de sysfs y realizar escrituras de archivo definitivamente extra\u00f1as. Por favor, consulte el informe para m\u00e1s detalles sobre los pasos de reproducci\u00f3n del problema.\n\nSolucione el problema realizando dos cambios. En primer lugar, mueva la kdamond_call() final para cancelar todas las solicitudes damon_call() existentes del contexto DAMON que termina, para que se realice antes del reinicio de ctx-\u0026gt;kdamond. Esto hace que cualquier c\u00f3digo que vea NULL en ctx-\u0026gt;kdamond pueda asumir con seguridad que el contexto ya no puede acceder a las solicitudes damon_call(). En segundo lugar, permita que damon_call() limpie los objetos damon_call_control que fueron a\u00f1adidos al contexto DAMON ya terminado, antes de devolver el error."
    }
  ],
  "id": "CVE-2026-23012",
  "lastModified": "2026-01-26T15:03:33.357",
  "metrics": {},
  "published": "2026-01-25T15:15:56.073",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/23b061f421eef03647b512f3df48861706c87db3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f9132fbc2e83baf2c45a77043672a63a675c9394"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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