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CVE-2022-50550

Estado: AnalizadaMedia (5.5)—

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

blk-iolatency: Fix memory leak on add_disk() failures

When a gendisk is successfully initialized but add_disk() fails such as when a loop device has invalid number of minor device numbers specified, blkcg_init_disk() is called during init and then blkcg_exit_disk() during error handling. Unfortunately, iolatency gets initialized in the former but doesn't get cleaned up in the latter.

This is because, in non-error cases, the cleanup is performed by del_gendisk() calling rq_qos_exit(), the assumption being that rq_qos policies, iolatency being one of them, can only be activated once the disk is fully registered and visible.

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That assumption is true for wbt and iocost, but not so for iolatency as it gets initialized before add_disk() is called.

It is desirable to lazy-init rq_qos policies because they are optional features and add to hot path overhead once initialized - each IO has to walk all the registered rq_qos policies. So, we want to switch iolatency to lazy init too. However, that's a bigger change. As a fix for the immediate problem, let's just add an extra call to rq_qos_exit() in blkcg_exit_disk(). This is safe because duplicate calls to rq_qos_exit() become noop's.

CVSS

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)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2022-50550",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
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        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
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  },
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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          ],
          "programFiles": [
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  "published": "2025-10-07T16:15:40.790",
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  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-401"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-iolatency: Fix memory leak on add_disk() failures\n\nWhen a gendisk is successfully initialized but add_disk() fails such as when\na loop device has invalid number of minor device numbers specified,\nblkcg_init_disk() is called during init and then blkcg_exit_disk() during\nerror handling. Unfortunately, iolatency gets initialized in the former but\ndoesn't get cleaned up in the latter.\n\nThis is because, in non-error cases, the cleanup is performed by\ndel_gendisk() calling rq_qos_exit(), the assumption being that rq_qos\npolicies, iolatency being one of them, can only be activated once the disk\nis fully registered and visible. That assumption is true for wbt and iocost,\nbut not so for iolatency as it gets initialized before add_disk() is called.\n\nIt is desirable to lazy-init rq_qos policies because they are optional\nfeatures and add to hot path overhead once initialized - each IO has to walk\nall the registered rq_qos policies. So, we want to switch iolatency to lazy\ninit too. However, that's a bigger change. As a fix for the immediate\nproblem, let's just add an extra call to rq_qos_exit() in blkcg_exit_disk().\nThis is safe because duplicate calls to rq_qos_exit() become noop's."
    }
  ],
  "lastModified": "2026-06-17T05:23:46.447",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
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              "versionEndExcluding": "6.0.17",
              "versionStartIncluding": "4.19"
            },
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}