sched/core: Avoid false migration warning for proxy donors

{
  "id": "85959052a71932f2a52512835fd8cf58fa76f965d039498ad6b018dad62950fa",
  "url": "https://osv.dev/vulnerability/CVE-2026-98418",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "sched/core: Avoid false migration warning for proxy donors",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: sched/core: Avoid false migration warning for proxy donors Proxy execution can move a blocked donor's scheduling context to the lock owner's CPU even when the donor is migration-disabled. The donor does not execute there, and its original execution CPU remains recorded in wake_cpu. set_task_cpu() warns unconditionally for migration-disabled tasks, so a subsequent proxy migration or the wakeup path returning the donor home triggers a false positive: moving a blocked scheduling context does not violate the migration-disabled execution context. For example, creating a mutex owner on CPU1 and a migration-disabled waiter on CPU0 can trigger the following warning: proxy_migrate_repro: donor blocking on CPU0 with migration disabled proxy_migrate_repro: donor moved from CPU0 to CPU1 WARNING: kernel/sched/core.c:3389 at set_task_cpu+0x1d3/0x280 ... Call Trace: try_to_wake_up+0x43f/0x780 __mutex_unlock_slowpath+0x330/0x540 owner_fn+0x9f/0xc0 [proxy_migrate_repro] ... proxy_migrate_repro: donor woke on CPU0, task_cpu=0 proxy_migrate_repro: completed Exclude blocked proxy donors from the warning. The proxy wakeup path restores an executable placement before clearing the blocked state.",
    "evidence": "osv:CVE-2026-98418",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.2.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98418",
      "aliases": [
        "CVE-2026-98418"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "b049b81bdff6fc6794200a4c7d7d910e2008d57f"
                },
                {
                  "fixed": "e4a442da49fff7619b3cb2988e477022dcea6688"
                },
                {
                  "fixed": "fe3c73d7bc769e7afc252f867a3421fe168b898d"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98418.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.1.0"
                },
                {
                  "fixed": "7.2.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98418.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:21.763729818Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/e4a442da49fff7619b3cb2988e477022dcea6688",
        "https://git.kernel.org/stable/c/fe3c73d7bc769e7afc252f867a3421fe168b898d",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98418.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98418",
        "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/2026/98xxx/CVE-2026-98418.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98418",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 487888,
  "published_at": "2026-10-14T13:27:48.406+00:00"
}