mm/compaction: fix UBSAN shift-out-of-bounds warning

{
  "id": "391fda4af4353a6df5bdd081b48bff378341f43be8679709e58955313c0cf238",
  "url": "https://osv.dev/vulnerability/CVE-2025-21815",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mm/compaction: fix UBSAN shift-out-of-bounds warning",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mm/compaction: fix UBSAN shift-out-of-bounds warning syzkaller reported a UBSAN shift-out-of-bounds warning of (1UL << order) in isolate_freepages_block(). The bogus compound_order can be any value because it is union with flags. Add back the MAX_PAGE_ORDER check to fix the warning.",
    "evidence": "osv:CVE-2025-21815",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.14",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.13.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-21815",
      "aliases": [
        "CVE-2025-21815"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "3da0272a4c7d0d37b47b28e87014f421296fc2be"
                },
                {
                  "fixed": "4491159774d973a9e2e998d25d8fbb20fada6dfa"
                },
                {
                  "fixed": "10b7d3eb535098ccd4c82a182a33655d8a0e5c88"
                },
                {
                  "fixed": "d1366e74342e75555af2648a2964deb2d5c92200"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21815.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.14"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.13.3"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21815.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.099132032Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/10b7d3eb535098ccd4c82a182a33655d8a0e5c88",
        "https://git.kernel.org/stable/c/4491159774d973a9e2e998d25d8fbb20fada6dfa",
        "https://git.kernel.org/stable/c/d1366e74342e75555af2648a2964deb2d5c92200",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21815.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21815",
        "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-2025-21815.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-21815",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 505046,
  "published_at": "2025-02-27T20:04:14.733+00:00"
}