9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN

{
  "id": "b863d7aa0183538bc39305b1b910589ab4206694b6a332a01707b380a167d767",
  "url": "https://osv.dev/vulnerability/CVE-2025-40305",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN p9_read_work() doesn't set Rworksched and doesn't do schedule_work(m->rq) if list_empty(&m->req_list). However, if the pipe is full, we need to read more data and this used to work prior to commit aaec5a95d59615 (\"pipe_read: don't wake up the writer if the pipe is still full\"). p9_read_work() does p9_fd_read() -> ... -> anon_pipe_read() which (before the commit above) triggered the unnecessary wakeup. This wakeup calls p9_pollwake() which kicks p9_poll_workfn() -> p9_poll_mux(), p9_poll_mux() will notice EPOLLIN and schedule_work(&m->rq). This no longer happens after the optimization above, change p9_fd_request() to use p9_poll_mux() instead of only checking for EPOLLOUT.",
    "evidence": "osv:CVE-2025-40305",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.17.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-40305",
      "aliases": [
        "CVE-2025-40305"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "aaec5a95d59615523db03dd53c2052f0a87beea7"
                },
                {
                  "fixed": "242531004d7de8c159f9bfadebe33fe8060b1046"
                },
                {
                  "fixed": "e8fe3f07a357c39d429e02ca34f740692d88967a"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40305.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.14.0"
                },
                {
                  "fixed": "6.17.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40305.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.806029695Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/242531004d7de8c159f9bfadebe33fe8060b1046",
        "https://git.kernel.org/stable/c/e8fe3f07a357c39d429e02ca34f740692d88967a",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40305.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-40305",
        "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/2025/40xxx/CVE-2025-40305.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-40305",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 497394,
  "published_at": "2025-12-08T00:46:30.327+00:00"
}