nvmet: Fix crash when a namespace is disabled

{
  "id": "d081ec97f9d0931ef67167de90383a1d8ce55a1e8df8e97d96cd619249e320b3",
  "url": "https://osv.dev/vulnerability/CVE-2025-21850",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nvmet: Fix crash when a namespace is disabled",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: nvmet: Fix crash when a namespace is disabled The namespace percpu counter protects pending I/O, and we can only safely diable the namespace once the counter drop to zero. Otherwise we end up with a crash when running blktests/nvme/058 (eg for loop transport): [ 2352.930426] [ T53909] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI [ 2352.930431] [ T53909] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] [ 2352.930434] [ T53909] CPU: 3 UID: 0 PID: 53909 Comm: kworker/u16:5 Tainted: G W 6.13.0-rc6 #232 [ 2352.930438] [ T53909] Tainted: [W]=WARN [ 2352.930440] [ T53909] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 [ 2352.930443] [ T53909] Workqueue: nvmet-wq nvme_loop_execute_work [nvme_loop] [ 2352.930449] [ T53909] RIP: 0010:blkcg_set_ioprio+0x44/0x180 as the queue is already torn down when calling submit_bio(); So we need to init the percpu counter in nvmet_ns_enable(), and wait for it to drop to zero in nvmet_ns_disable() to avoid having I/O pending after the namespace has been disabled.",
    "evidence": "osv:CVE-2025-21850",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.13.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2025-21850",
      "aliases": [
        "CVE-2025-21850"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                },
                {
                  "fixed": "cc0607594f6813342b27c752c6fb6f6eb9980cb5"
                },
                {
                  "fixed": "4082326807072b71496501b6a0c55ffe8d5092a5"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21850.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.13.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21850.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:53.418202549Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/4082326807072b71496501b6a0c55ffe8d5092a5",
        "https://git.kernel.org/stable/c/cc0607594f6813342b27c752c6fb6f6eb9980cb5",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21850.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21850",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21850.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-21850",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 522031,
  "published_at": "2025-03-12T09:42:05.761+00:00"
}