{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2021-47555",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: vlan: fix underflow for the real_dev refcnt\n\nInject error before dev_hold(real_dev) in register_vlan_dev(),\nand execute the following testcase:\n\nip link add dev dummy1 type dummy\nip link add name dummy1.100 link dummy1 type vlan id 100\nip link del dev dummy1\n\nWhen the dummy netdevice is removed, we will get a WARNING as following:\n\n=======================================================================\nrefcount_t: decrement hit 0; leaking memory.\nWARNING: CPU: 2 PID: 0 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0\n\nand an endless loop of:\n\n=======================================================================\nunregister_netdevice: waiting for dummy1 to become free. Usage count = -1073741824\n\nThat is because dev_put(real_dev) in vlan_dev_free() be called without\ndev_hold(real_dev) in register_vlan_dev(). It makes the refcnt of real_dev\nunderflow.\n\nMove the dev_hold(real_dev) to vlan_dev_init() which is the call-back of\nndo_init(). That makes dev_hold() and dev_put() for vlan's real_dev\nsymmetrical."
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "700602b662d7",
                                            "version_value": "5e44178864b3"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "e04a7a84bb77",
                                            "version_value": "6e800ee43218"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "21032425c36f",
                                            "version_value": "f7fc72a508cf"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "563bcbae3ba2",
                                            "version_value": "01d9cc2dea3f"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "5.4.160",
                                            "version_value": "5.4.163"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "5.10.80",
                                            "version_value": "5.10.83"
                                        },
                                        {
                                            "version_affected": "<",
                                            "version_name": "5.15.3",
                                            "version_value": "5.15.6"
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/5e44178864b38dd70b877985abd7d86fdb95f27d",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/5e44178864b38dd70b877985abd7d86fdb95f27d"
            },
            {
                "url": "https://git.kernel.org/stable/c/6e800ee43218a56acc93676bbb3d93b74779e555",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/6e800ee43218a56acc93676bbb3d93b74779e555"
            },
            {
                "url": "https://git.kernel.org/stable/c/f7fc72a508cf115c273a7a29350069def1041890",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/f7fc72a508cf115c273a7a29350069def1041890"
            },
            {
                "url": "https://git.kernel.org/stable/c/01d9cc2dea3fde3bad6d27f464eff463496e2b00",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/01d9cc2dea3fde3bad6d27f464eff463496e2b00"
            }
        ]
    },
    "generator": {
        "engine": "bippy-a5840b7849dd"
    }
}