drm/amd/display: Atomize IRQ register read/modify/write ops

{
  "id": "6a4dc8eb6c6c01822e680638ef4de2894ac3e09945f835c9816c0ba4b6f5e5ee",
  "url": "https://osv.dev/vulnerability/CVE-2026-98654",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "drm/amd/display: Atomize IRQ register read/modify/write ops",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Atomize IRQ register read/modify/write ops [Why] The OTG_GLOBAL_SYNC_STATUS register controls various HW IRQ sources for the output timing generator (OTG). VUPDATE_NO_LOCK is one of them. To enable the IRQ, driver sets the VUPDATE_NO_LOCK_EN bit in the GLOBAL_SYNC_STATUS register. To ack the IRQ after it fires, the driver sets the VUPDATE_NO_LOCK_CLEAR bit in the same GLOBAL_SYNC_STATUS register. The bit sets are done through read/modify/write operations, which are not atomic. Thus, the following race is possible: Thread A: IRQ handler: *HW IRQ fires* # IRQ disable val = read(GLOBAL_SYNC_STATUS) unset(val, VUPDATE_NO_LOCK_EN) write(val, GLOBAL_SYNC_STATUS) # ACK reads VUPDATE_NO_LOCK_EN unset val1 = read(GLOBAL_SYNC_STATUS) set(val1, VUPDATE_NO_LOCK_CLEAR) # IRQ enable val = read(GLOBAL_SYNC_STATUS) set(val, VUPDATE_NO_LOCK_EN) write(val, GLOBAL_SYNC_STATUS) # BAD! clears VUPDATE_NO_LOCK_EN write(val1, GLOBAL_SYNC_STATUS) Regarding the tagged Fixes: change, it appears the change made this race more likely to occur. Since VUPDATE_NO_LOCK is now the sole IRQ source for vblank handling, a single race on high refresh panels can lead to a time out. [How] The GLOBAL_SYNC_STATUS register is only one example, other IRQ control registers also share the same scheme. On top of GLOBAL_SYNC_STATUS, let's clean up those as well. To keep things simple, Let's atomize the IRQ rmw ops via a single driver-wide ",
    "evidence": "osv:CVE-2026-98654",
    "products": [],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98654",
      "aliases": [
        "CVE-2026-98654"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "c87e6635d2db02c88ae8d09529362da672d34770"
                },
                {
                  "fixed": "63e19ef3ddab806c472748c825f4dc88dcd994e8"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98654.json"
          }
        }
      ],
      "modified": "2026-10-19T02:47:02.643815507Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
        "https://git.kernel.org/stable/c/63e19ef3ddab806c472748c825f4dc88dcd994e8",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98654.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98654"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98654.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98654",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 372263,
  "published_at": "2026-10-18T15:20:25.64+00:00"
}