CVE-2026-74593 (GCVE-0-2026-74593)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:31 – Updated: 2026-08-23 12:47
VLAI
Title
sched_ext: Take cgroup_lock() first in scx_cgroup_lock()
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Take cgroup_lock() first in scx_cgroup_lock() scx_cgroup_lock() write-locks scx_cgroup_ops_rwsem and then takes cgroup_lock(), which can deadlock through kernfs: scx enable/disable cgroup rmdir cpu.weight write ------------------ ------------ ---------------- cgroup_lock() percpu_down_write(rwsem) cgroup_lock() kernfs_get_active() percpu_down_read(rwsem) kernfs_drain() The enable path waits for the rmdir to release cgroup_mutex. The rmdir, deactivating the cpu controller's files, waits in kernfs_drain() for the write's active reference. The write, in scx_group_set_weight(), waits for the rwsem behind the pending writer. Take cgroup_lock() first. The set_* paths take no cgroup locks inside the read side, so a pending write-lock then only waits for read sections that always run to completion, and no dependency from the rwsem back to cgroup_mutex remains.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6664 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a5bd6ba30b3364354269b81ac55c2edca9a96d6d , < 2ca6b43edf83f8fc368cc3094ee5f3b1e8e0b0f0 (git)
Affected: a5bd6ba30b3364354269b81ac55c2edca9a96d6d , < a054c9ffa9b7a0dffb763837b91ac9d381ec6d10 (git)
Affected: a5bd6ba30b3364354269b81ac55c2edca9a96d6d , < 5f8b69642d18e1f3e11996707842ac530444e959 (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.46 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext/ext.c"
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          "vendor": "Linux",
          "versions": [
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              "operator": "OR"
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Take cgroup_lock() first in scx_cgroup_lock()\n\nscx_cgroup_lock() write-locks scx_cgroup_ops_rwsem and then takes\ncgroup_lock(), which can deadlock through kernfs:\n\n  scx enable/disable         cgroup rmdir           cpu.weight write\n  ------------------         ------------           ----------------\n                             cgroup_lock()\n  percpu_down_write(rwsem)\n  cgroup_lock()\n                                                    kernfs_get_active()\n                                                    percpu_down_read(rwsem)\n                             kernfs_drain()\n\nThe enable path waits for the rmdir to release cgroup_mutex. The rmdir,\ndeactivating the cpu controller\u0027s files, waits in kernfs_drain() for the\nwrite\u0027s active reference. The write, in scx_group_set_weight(), waits for\nthe rwsem behind the pending writer.\n\nTake cgroup_lock() first. The set_* paths take no cgroup locks inside the\nread side, so a pending write-lock then only waits for read sections that\nalways run to completion, and no dependency from the rwsem back to\ncgroup_mutex remains."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-23T12:47:36.437Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/2ca6b43edf83f8fc368cc3094ee5f3b1e8e0b0f0"
        },
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          "url": "https://git.kernel.org/stable/c/a054c9ffa9b7a0dffb763837b91ac9d381ec6d10"
        },
        {
          "url": "https://git.kernel.org/stable/c/5f8b69642d18e1f3e11996707842ac530444e959"
        }
      ],
      "title": "sched_ext: Take cgroup_lock() first in scx_cgroup_lock()",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74593",
    "datePublished": "2026-08-22T15:31:44.160Z",
    "dateReserved": "2026-08-15T05:44:03.919Z",
    "dateUpdated": "2026-08-23T12:47:36.437Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-10-16",
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      "percentile": "0.09976"
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                "product": "Linux",
                "programFiles": [
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                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
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          }
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Take cgroup_lock() first in scx_cgroup_lock()\n\nscx_cgroup_lock() write-locks scx_cgroup_ops_rwsem and then takes\ncgroup_lock(), which can deadlock through kernfs:\n\n  scx enable/disable         cgroup rmdir           cpu.weight write\n  ------------------         ------------           ----------------\n                             cgroup_lock()\n  percpu_down_write(rwsem)\n  cgroup_lock()\n                                                    kernfs_get_active()\n                                                    percpu_down_read(rwsem)\n                             kernfs_drain()\n\nThe enable path waits for the rmdir to release cgroup_mutex. The rmdir,\ndeactivating the cpu controller\u0027s files, waits in kernfs_drain() for the\nwrite\u0027s active reference. The write, in scx_group_set_weight(), waits for\nthe rwsem behind the pending writer.\n\nTake cgroup_lock() first. The set_* paths take no cgroup locks inside the\nread side, so a pending write-lock then only waits for read sections that\nalways run to completion, and no dependency from the rwsem back to\ncgroup_mutex remains."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nsched_ext: Tomar cgroup_lock() primero en scx_cgroup_lock()\n\nscx_cgroup_lock() bloquea en modo escritura scx_cgroup_ops_rwsem y luego toma cgroup_lock(), lo que puede causar un interbloqueo a trav\u00e9s de kernfs:\n\n  scx habilitar/deshabilitar         cgroup rmdir           cpu.weight escritura\n  -------------------------         ------------           -------------------\n                                    cgroup_lock()\n  percpu_down_write(rwsem)\n  cgroup_lock()\n                                                           kernfs_get_active()\n                                                           percpu_down_read(rwsem)\n                                    kernfs_drain()\n\nLa ruta de habilitaci\u00f3n espera a que el rmdir libere cgroup_mutex. El rmdir, al desactivar los archivos del controlador de CPU, espera en kernfs_drain() la referencia activa de la escritura. La escritura, en scx_group_set_weight(), espera al rwsem detr\u00e1s del escritor pendiente.\n\nTomar cgroup_lock() primero. Las rutas set_* no toman bloqueos de cgroup dentro del lado de lectura, por lo que un bloqueo de escritura pendiente entonces solo espera por secciones de lectura que siempre se ejecutan hasta su finalizaci\u00f3n, y no queda ninguna dependencia del rwsem de vuelta a cgroup_mutex."
          }
        ],
        "id": "CVE-2026-74593",
        "lastModified": "2026-10-14T13:10:00.187",
        "metrics": {},
        "published": "2026-08-22T16:16:31.573",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/2ca6b43edf83f8fc368cc3094ee5f3b1e8e0b0f0"
          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5f8b69642d18e1f3e11996707842ac530444e959"
          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
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      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-24T11:54:05+00:00",
      "cve": "CVE-2026-74593",
      "id": "CVE-2026-74593",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: sched_ext: Take cgroup_lock() first in scx_cgroup_lock()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74593.json",
      "version": "3"
    }
  }
}



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