md: Don't ignore read-only array in md_check_recovery()

{
  "id": "83c66f3db51bb6c0a9d75f1433524c740c603118328b4af6f3f1c91318ddf648",
  "url": "https://osv.dev/vulnerability/CVE-2024-26757",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "md: Don't ignore read-only array in md_check_recovery()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: md: Don't ignore read-only array in md_check_recovery() Usually if the array is not read-write, md_check_recovery() won't register new sync_thread in the first place. And if the array is read-write and sync_thread is registered, md_set_readonly() will unregister sync_thread before setting the array read-only. md/raid follow this behavior hence there is no problem. After commit f52f5c71f3d4 (\"md: fix stopping sync thread\"), following hang can be triggered by test shell/integrity-caching.sh: 1) array is read-only. dm-raid update super block: rs_update_sbs ro = mddev->ro mddev->ro = 0 -> set array read-write md_update_sb 2) register new sync thread concurrently. 3) dm-raid set array back to read-only: rs_update_sbs mddev->ro = ro 4) stop the array: raid_dtr md_stop stop_sync_thread set_bit(MD_RECOVERY_INTR, &mddev->recovery); md_wakeup_thread_directly(mddev->sync_thread); wait_event(..., !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) 5) sync thread done: md_do_sync set_bit(MD_RECOVERY_DONE, &mddev->recovery); md_wakeup_thread(mddev->thread); 6) daemon thread can't unregister sync thread: md_check_recovery if (!md_is_rdwr(mddev) && !test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) return; -> -> MD_RECOVERY_RUNNING can't be cleared, hence step 4 hang; The root cause is that dm-raid manipulate 'mddev->ro' by itself, however, dm-raid really should stop sync thread before setting the array read-only. Unfortunately,",
    "evidence": "osv:CVE-2024-26757",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.7.7",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2024-26757",
      "aliases": [
        "CVE-2024-26757"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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": "2ea169c5a0b1134d573d07fc27a16f327ad0e7d3"
                },
                {
                  "fixed": "55a48ad2db64737f7ffc0407634218cc6e4c513b"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-26757.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.8.0"
                },
                {
                  "fixed": "6.7.7"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-26757.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.043457743Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/2ea169c5a0b1134d573d07fc27a16f327ad0e7d3",
        "https://git.kernel.org/stable/c/55a48ad2db64737f7ffc0407634218cc6e4c513b",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/26xxx/CVE-2024-26757.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-26757",
        "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/2024/26xxx/CVE-2024-26757.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-26757",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 488011,
  "published_at": "2024-04-03T17:00:41.633+00:00"
}