{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-40347",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-40347"
  ],
  "published": "2025-12-16T13:30:44Z",
  "summary": "net: enetc: fix the deadlock of enetc_mdio_lock",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: enetc: fix the deadlock of enetc_mdio_lock\n\nAfter applying the workaround for err050089, the LS1028A platform\nexperiences RCU stalls on RT kernel. This issue is caused by the\nrecursive acquisition of the read lock enetc_mdio_lock. Here list some\nof the call stacks identified under the enetc_poll path that may lead to\na deadlock:\n\nenetc_poll\n  -> enetc_lock_mdio\n  -> enetc_clean_rx_ring OR napi_complete_done\n     -> napi_gro_receive\n        -> enetc_start_xmit\n           -> enetc_lock_mdio\n           -> enetc_map_tx_buffs\n           -> enetc_unlock_mdio\n  -> enetc_unlock_mdio\n\nAfter enetc_poll acquires the read lock, a higher-priority writer attempts\nto acquire the lock, causing preemption. The writer detects that a\nread lock is already held and is scheduled out. However, readers under\nenetc_poll cannot acquire the read lock again because a writer is already\nwaiting, leading to a thread hang.\n\nCurrently, the deadlock is avoided by adjusting enetc_lock_mdio to prevent\nrecursive lock acquisition.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.175",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-40347"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a649161526736f48bcc592e3a412e5bcd7dd9e24"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2781ca82ce8cad263d80b617addb727e6a84c9e5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1f92f5bd057a4fad9dab6af17963cdd21e5da6ed"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2e55a49dc3b2a6b23329e4fbbd8a5feb20e220aa"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/50bd33f6b3922a6b760aa30d409cae891cec8fb5"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.5,
      "cvss_v3_severity": "High",
      "scenario": "AV:N - The deadlock is driven from the enetc RX datapath (`enetc_poll` \u2192 `napi_gro_receive` \u2192 stack \u2192 `enetc_start_xmit`), reached purely by packets arriving on the Ethernet interface, including routed IP traffic from arbitrary remote networks. No L2 adjacency or local access is needed \u2014 a plain ICMP/TCP flow that elicits a reply or is forwarded suffices.\nAC:L - The attacker directly creates the recursive read-lock condition by sustaining inbound traffic that triggers a transmit from within the RX softirq, and the competing MDIO writer occurs many times per second from the periodic phylib/phylink state machine, so the collision is reached reliably within seconds and can be retried indefinitely.\nPR:N - The vulnerable path is the unauthenticated packet-receive path of the NIC driver; no credentials, capabilities, or local account are required \u2014 merely sending traffic to (or through) the affected interface is enough.\nUI:N - No victim action is needed; the deadlock arises from normal kernel-side packet processing and background PHY polling that run without any user involvement.\nS:U - The lock inversion hangs kernel threads within the same security authority as the affected kernel; no VM, IOMMU, or sandbox boundary is crossed.\nC:N - This is a pure lock-ordering/recursion defect with no memory corruption, out-of-bounds access, or exposure of kernel data to the attacker.\nI:N - No data is modified and no write primitive is produced; the failure mode is threads blocking on an rt_mutex-backed rwlock, not memory corruption.\nA:H - The recursive read-lock acquisition deadlocks the NAPI poll thread against a waiting MDIO writer, producing RCU stalls, hung tasks, and permanent loss of network processing on the interface \u2014 a remotely inducible, unrecoverable denial of service."
    }
  }
}