net: let net.core.dev_weight always be non-zero

{
  "id": "7738f013255d00b4dfdef35d65c8c0bf8b2b44f8ee5ce349985840585459c27c",
  "url": "https://osv.dev/vulnerability/CVE-2025-21806",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: let net.core.dev_weight always be non-zero",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: net: let net.core.dev_weight always be non-zero The following problem was encountered during stability test: (NULL net_device): NAPI poll function process_backlog+0x0/0x530 \\ returned 1, exceeding its budget of 0. ------------[ cut here ]------------ list_add double add: new=ffff88905f746f48, prev=ffff88905f746f48, \\ next=ffff88905f746e40. WARNING: CPU: 18 PID: 5462 at lib/list_debug.c:35 \\ __list_add_valid_or_report+0xf3/0x130 CPU: 18 UID: 0 PID: 5462 Comm: ping Kdump: loaded Not tainted 6.13.0-rc7+ RIP: 0010:__list_add_valid_or_report+0xf3/0x130 Call Trace: ? __warn+0xcd/0x250 ? __list_add_valid_or_report+0xf3/0x130 enqueue_to_backlog+0x923/0x1070 netif_rx_internal+0x92/0x2b0 __netif_rx+0x15/0x170 loopback_xmit+0x2ef/0x450 dev_hard_start_xmit+0x103/0x490 __dev_queue_xmit+0xeac/0x1950 ip_finish_output2+0x6cc/0x1620 ip_output+0x161/0x270 ip_push_pending_frames+0x155/0x1a0 raw_sendmsg+0xe13/0x1550 __sys_sendto+0x3bf/0x4e0 __x64_sys_sendto+0xdc/0x1b0 do_syscall_64+0x5b/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e The reproduction command is as follows: sysctl -w net.core.dev_weight=0 ping 127.0.0.1 This is because when the napi's weight is set to 0, process_backlog() may return 0 and clear the NAPI_STATE_SCHED bit of napi->state, causing this napi to be re-polled in net_rx_action() until __do_softirq() times out. Since the NAPI_STATE_SCHED bit has been cleared, napi_schedule_rps() can be retriggered in enqueu",
    "evidence": "osv:CVE-2025-21806",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.4.291",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.235",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.179",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.129",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.76",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.13",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.13.2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-21806",
      "aliases": [
        "CVE-2025-21806"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "e3876605450979fe52a1a03e7eb78a89bf59e76a"
                },
                {
                  "fixed": "d0e0f9c8218826926d7692980c98236d9f21fd3c"
                },
                {
                  "fixed": "c337c08819a4ec49edfdcd8fc46fbee120d8a5b2"
                },
                {
                  "fixed": "0e2f1d93d287d544d26f8ff293ea820a8079b9f8"
                },
                {
                  "fixed": "5860abbf15eeb61838b5e32e721ba67b0aa84450"
                },
                {
                  "fixed": "6ce38b5a6a49e65bad163162a54cb3f104c40b48"
                },
                {
                  "fixed": "33e2168788f8fb5cb8bd4f36cb1ef37d1d34dada"
                },
                {
                  "fixed": "1489824e5226a26841c70639ebd2d1aed390764b"
                },
                {
                  "fixed": "d1f9f79fa2af8e3b45cffdeef66e05833480148a"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21806.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.12"
                },
                {
                  "fixed": "5.4.291"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
                },
                {
                  "fixed": "5.10.235"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.179"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.129"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.76"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.13"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.13.2"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21806.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.166070045Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-265688.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-503939.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-784472.html",
        "https://git.kernel.org/stable/c/0e2f1d93d287d544d26f8ff293ea820a8079b9f8",
        "https://git.kernel.org/stable/c/1489824e5226a26841c70639ebd2d1aed390764b",
        "https://git.kernel.org/stable/c/33e2168788f8fb5cb8bd4f36cb1ef37d1d34dada",
        "https://git.kernel.org/stable/c/5860abbf15eeb61838b5e32e721ba67b0aa84450",
        "https://git.kernel.org/stable/c/6ce38b5a6a49e65bad163162a54cb3f104c40b48",
        "https://git.kernel.org/stable/c/c337c08819a4ec49edfdcd8fc46fbee120d8a5b2",
        "https://git.kernel.org/stable/c/d0e0f9c8218826926d7692980c98236d9f21fd3c",
        "https://git.kernel.org/stable/c/d1f9f79fa2af8e3b45cffdeef66e05833480148a",
        "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html",
        "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21806.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21806",
        "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-2025-21806.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-21806",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 496955,
  "published_at": "2025-02-27T20:00:58.918+00:00"
}