riscv/mm: use physical alignment for vmemmap_start_pfn

{
  "id": "cb98245c1fff2c8cdeb189177404c2626a2456dc79b3f15c3a8de2a94b486fa1",
  "url": "https://osv.dev/vulnerability/CVE-2026-80682",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "riscv/mm: use physical alignment for vmemmap_start_pfn",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: riscv/mm: use physical alignment for vmemmap_start_pfn RISC-V computes vmemmap_start_pfn by rounding phys_ram_base down to VMEMMAP_ADDR_ALIGN. That alignment must therefore be expressed in the physical-address domain. Commit 476849b0fba4 (\"riscv/mm: align vmemmap to maximal folio size\") attempted to account for the maximal folio alignment by feeding MAX_FOLIO_VMEMMAP_ALIGN directly into VMEMMAP_ADDR_ALIGN. However, MAX_FOLIO_VMEMMAP_ALIGN is measured in bytes of struct page storage, whereas VMEMMAP_ADDR_ALIGN is used to align a physical address. The mask-based compound_info encoding requires pfn_to_page(0) to be naturally aligned to MAX_FOLIO_VMEMMAP_ALIGN. Commit 9f94db4c7eaa (\"mm/sparse: check memmap alignment for compound_info_has_mask()\") added a check for that requirement and exposed the unit mismatch on systems such as QEMU virt, where the DRAM base is not aligned to MAX_FOLIO_NR_PAGES * PAGE_SIZE. Here is the log: [ 0.000000][ C0] ------------[ cut here ]------------ [ 0.000000][ C0] WARNING: mm/sparse.c:365 at sparse_init+0x58a/0x6fe, CPU#0: swapper/0 [ 0.000000][ C0] Modules linked in: [ 0.000000][ C0] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.2.0-rc3-g1d8304bdd65f #2 PREEMPT [ 0.000000][ C0] Hardware name: riscv-virtio,qemu (DT) [ 0.000000][ C0] epc : sparse_init+0x58a/0x6fe [ 0.000000][ C0] ra : sparse_init+0x58a/0x6fe [ 0.000000][ C0] epc : ffffffff86851c88 ra : ffffffff86851c88 sp : ffffff",
    "evidence": "osv:CVE-2026-80682",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.1.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-80682",
      "aliases": [
        "CVE-2026-80682"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/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": [
                {
                  "introduced": "476849b0fba4450f5adf22196bcff9c24c673bc4"
                },
                {
                  "fixed": "11ad86830a78ea4e1942afc73c10e4ca8e69e03f"
                },
                {
                  "fixed": "45ebe4540817cb540a59e4dc04014ac5dddc9990"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80682.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.1.0"
                },
                {
                  "fixed": "7.1.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80682.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.086941147Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/11ad86830a78ea4e1942afc73c10e4ca8e69e03f",
        "https://git.kernel.org/stable/c/45ebe4540817cb540a59e4dc04014ac5dddc9990",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80682.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-80682",
        "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/2026/80xxx/CVE-2026-80682.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-80682",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519918,
  "published_at": "2026-08-28T06:52:49.498+00:00"
}