Here are the NetworkManager logs when I first disabled my networking (note that ensp5s0 does get its link up reported correctly, but no traffic seems to go over it):
Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1626] manager: disable requested (sleeping: no enabled: yes) Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1627] manager: NetworkManager state is now ASLEEP Apr 23 09:42:54 surprise dbus-daemon[1280]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.9' (uid=0 pid=1281 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined") Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1654] device (enp5s0): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'managed') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1695] device (virbr0): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1703] device (lxdbr0): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1711] device (docker0): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1718] device (tun0): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1744] device (mpqemubr0): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1754] device (tap-2eb5e2d1a05): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1756] device (mpqemubr0): bridge port tap-2eb5e2d1a05 was detached Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1756] device (tap-2eb5e2d1a05): released from master device mpqemubr0 Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1764] device (tap-8b9ffd8bf3f): state change: activated -> deactivating (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1765] device (mpqemubr0): bridge port tap-8b9ffd8bf3f was detached Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.1765] device (tap-8b9ffd8bf3f): released from master device mpqemubr0 Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2065] device (enp5s0): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'managed') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2124] dhcp4 (enp5s0): canceled DHCP transaction Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2124] dhcp4 (enp5s0): state changed extended -> done Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2132] dhcp6 (enp5s0): canceled DHCP transaction Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2133] dhcp6 (enp5s0): state changed bound -> done Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2455] vpn-connection[0x55a3ea09c330,6c36b60c-84e0-42b3-85d0-8ddb549add83,"us-dwatkins",0]: VPN plugin: state changed: stopping (5) Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2455] vpn-connection[0x55a3ea09c330,6c36b60c-84e0-42b3-85d0-8ddb549add83,"us-dwatkins",0]: VPN plugin: state changed: stopped (6) Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.2466] device (enp5s0): state change: disconnected -> unmanaged (reason 'sleeping', sys-iface-state: 'managed') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.3121] device (virbr0): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.3588] device (lxdbr0): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.3655] device (docker0): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.3760] device (tun0): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.3819] device (mpqemubr0): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4358] device (tap-2eb5e2d1a05): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4381] device (tap-8b9ffd8bf3f): state change: deactivating -> disconnected (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <warn> [1587649374.4413] dns-sd-resolved[61f91f275b16a93b]: send-updates failed to update systemd-resolved: GDBus.Error:org.freedesktop.resolve1.NoSuchLink: Link 36 not known Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4469] device (tun0): state change: disconnected -> unmanaged (reason 'unmanaged', sys-iface-state: 'removed') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4475] device (virbr0): state change: disconnected -> unmanaged (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4520] device (lxdbr0): state change: disconnected -> unmanaged (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4527] device (docker0): state change: disconnected -> unmanaged (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4534] device (mpqemubr0): state change: disconnected -> unmanaged (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4540] device (tap-2eb5e2d1a05): state change: disconnected -> unmanaged (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:54 surprise NetworkManager[1281]: <info> [1587649374.4545] device (tap-8b9ffd8bf3f): state change: disconnected -> unmanaged (reason 'sleeping', sys-iface-state: 'external') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.1783] manager: enable requested (sleeping: no enabled: no) Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.1784] device (enp5s0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'managed') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3035] device (virbr0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3039] device (virbr0-nic): released from master device virbr0 Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3046] device (lxdbr0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3050] device (veth873d95da): released from master device lxdbr0 Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3058] device (mpqemubr0): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3061] device (mpqemubr0-dummy): released from master device mpqemubr0 Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3061] device (tap-2eb5e2d1a05): released from master device mpqemubr0 Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3061] device (tap-8b9ffd8bf3f): released from master device mpqemubr0 Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3068] device (tap-2eb5e2d1a05): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3077] device (tap-8b9ffd8bf3f): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3088] manager: NetworkManager state is now DISCONNECTED Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3092] device (lxdbr0): state change: unavailable -> unmanaged (reason 'connection-assumed', sys-iface-state: 'managed') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3112] device (virbr0): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3118] device (mpqemubr0): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3123] device (tap-2eb5e2d1a05): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed') Apr 23 09:42:56 surprise NetworkManager[1281]: <info> [1587649376.3128] device (tap-8b9ffd8bf3f): state change: unavailable -> disconnected (reason 'none', sys-iface-state: 'managed') Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8952] device (enp5s0): carrier: link connected Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8954] device (enp5s0): state change: unavailable -> disconnected (reason 'carrier-changed', sys-iface-state: 'managed') Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8963] policy: auto-activating connection 'Wired connection 1' (a2c1dab1-5570-31cb-9d13-9912bc640c0b) Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8968] device (enp5s0): Activation: starting connection 'Wired connection 1' (a2c1dab1-5570-31cb-9d13-9912bc640c0b) Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8969] device (enp5s0): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed') Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8972] manager: NetworkManager state is now CONNECTING Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8974] device (enp5s0): state change: prepare -> config (reason 'none', sys-iface-state: 'managed') Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8979] device (enp5s0): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed') Apr 23 09:42:58 surprise NetworkManager[1281]: <info> [1587649378.8981] dhcp4 (enp5s0): activation: beginning transaction (timeout in 45 seconds) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1874464 Title: NETDEV WATCHDOG: enp5s0 (r8169): transmit queue 0 timed out Status in linux package in Ubuntu: Confirmed Bug description: Running focal on a desktop, I accidentally clicked "Enable networking" in nm-applet, disabling my networking. When I clicked it again to reenable it, my networking did not return. After unsuccessfully poking at it for a while, I rebooted and saw the below (and still no networking). `rmmod r8169; modprobe r8169` had no (apparent) effect, nor did further reboots. I rebooted onto two different kernels, both exhibited the same behaviour: 5.4.0-21-generic, 5.4.0-26-generic. I was finally only able to restore networking by _rebooting into Windows_ and then rebooting back into Ubuntu. (My supposition is that NetworkManager/the kernel set *waves hands* something on the network card that persists across boots when it was disabled, and that wasn't correctly unset when I reenabled networking (or on following boots), but Windows _does_ correctly handle that case on boot, and reset it to a working state.) Apr 23 10:07:43 surprise kernel: ------------[ cut here ]------------ Apr 23 10:07:43 surprise kernel: NETDEV WATCHDOG: enp5s0 (r8169): transmit queue 0 timed out Apr 23 10:07:43 surprise kernel: WARNING: CPU: 9 PID: 0 at net/sched/sch_generic.c:447 dev_watchdog+0x258/0x260 Apr 23 10:07:43 surprise kernel: Modules linked in: zfs(PO) zunicode(PO) zavl(PO) icp(PO) zcommon(PO) znvpair(PO) spl(O) zlua(PO) xt_comment dummy xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp ip6table_mangle ip6table_nat iptable_mangle iptable_nat nf_> Apr 23 10:07:43 surprise kernel: autofs4 btrfs xor zstd_compress raid6_pq libcrc32c dm_crypt hid_microsoft ff_memless hid_logitech_hidpp hid_logitech_dj hid_generic usbhid hid nvidia_drm(POE) nvidia_modeset(POE) nvidia(POE) crct10dif_pclmul crc32_pclmul ghash_clmulni_intel drm_km> Apr 23 10:07:43 surprise kernel: CPU: 9 PID: 0 Comm: swapper/9 Tainted: P OE 5.4.0-26-generic #30-Ubuntu Apr 23 10:07:43 surprise kernel: Hardware name: Gigabyte Technology Co., Ltd. B450M DS3H/B450M DS3H-CF, BIOS F4 01/25/2019 Apr 23 10:07:43 surprise kernel: RIP: 0010:dev_watchdog+0x258/0x260 Apr 23 10:07:43 surprise kernel: Code: 85 c0 75 e5 eb 9f 4c 89 ff c6 05 bf 06 e8 00 01 e8 6d bb fa ff 44 89 e9 4c 89 fe 48 c7 c7 50 6d a3 b4 48 89 c2 e8 83 3f 71 ff <0f> 0b eb 80 0f 1f 40 00 0f 1f 44 00 00 55 48 89 e5 41 57 49 89 d7 Apr 23 10:07:43 surprise kernel: RSP: 0018:ffffa90d40378e30 EFLAGS: 00010286 Apr 23 10:07:43 surprise kernel: RAX: 0000000000000000 RBX: ffff8a7578b00400 RCX: 0000000000000000 Apr 23 10:07:43 surprise kernel: RDX: ffff8a758ee67740 RSI: ffff8a758ee578c8 RDI: 0000000000000300 Apr 23 10:07:43 surprise kernel: RBP: ffffa90d40378e60 R08: ffff8a758ee578c8 R09: 0000000000000004 Apr 23 10:07:43 surprise kernel: R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001 Apr 23 10:07:43 surprise kernel: R13: 0000000000000000 R14: ffff8a758cadc480 R15: ffff8a758cadc000 Apr 23 10:07:43 surprise kernel: FS: 0000000000000000(0000) GS:ffff8a758ee40000(0000) knlGS:0000000000000000 Apr 23 10:07:43 surprise kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Apr 23 10:07:43 surprise kernel: CR2: 00007f4d2000d5eb CR3: 00000003fcfe2000 CR4: 00000000003406e0 Apr 23 10:07:43 surprise kernel: Call Trace: Apr 23 10:07:43 surprise kernel: <IRQ> Apr 23 10:07:43 surprise kernel: ? pfifo_fast_enqueue+0x150/0x150 Apr 23 10:07:43 surprise kernel: call_timer_fn+0x32/0x130 Apr 23 10:07:43 surprise kernel: __run_timers.part.0+0x180/0x280 Apr 23 10:07:43 surprise kernel: ? tick_sched_handle+0x33/0x60 Apr 23 10:07:43 surprise kernel: ? tick_sched_timer+0x3d/0x80 Apr 23 10:07:43 surprise kernel: ? ktime_get+0x3e/0xa0 Apr 23 10:07:43 surprise kernel: run_timer_softirq+0x2a/0x50 Apr 23 10:07:43 surprise kernel: __do_softirq+0xe1/0x2d6 Apr 23 10:07:43 surprise kernel: ? hrtimer_interrupt+0x13b/0x220 Apr 23 10:07:43 surprise kernel: irq_exit+0xae/0xb0 Apr 23 10:07:43 surprise kernel: smp_apic_timer_interrupt+0x7b/0x140 Apr 23 10:07:43 surprise kernel: apic_timer_interrupt+0xf/0x20 Apr 23 10:07:43 surprise kernel: </IRQ> Apr 23 10:07:43 surprise kernel: RIP: 0010:cpuidle_enter_state+0xc5/0x450 Apr 23 10:07:43 surprise kernel: Code: ff e8 df 0d 81 ff 80 7d c7 00 74 17 9c 58 0f 1f 44 00 00 f6 c4 02 0f 85 65 03 00 00 31 ff e8 32 7a 87 ff fb 66 0f 1f 44 00 00 <45> 85 ed 0f 88 8f 02 00 00 49 63 cd 4c 8b 7d d0 4c 2b 7d c8 48 8d Apr 23 10:07:43 surprise kernel: RSP: 0018:ffffa90d4016fe38 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 Apr 23 10:07:43 surprise kernel: RAX: ffff8a758ee6ad00 RBX: ffffffffb4d69160 RCX: 000000000000001f Apr 23 10:07:43 surprise kernel: RDX: 0000000000000000 RSI: 00000000239f52d0 RDI: 0000000000000000 Apr 23 10:07:43 surprise kernel: RBP: ffffa90d4016fe78 R08: 0000011276ac078f R09: 00000000000148ba Apr 23 10:07:43 surprise kernel: R10: ffff8a758ee69a00 R11: ffff8a758ee699e0 R12: ffff8a757a318000 Apr 23 10:07:43 surprise kernel: R13: 0000000000000002 R14: 0000000000000002 R15: ffff8a757a318000 Apr 23 10:07:43 surprise kernel: ? cpuidle_enter_state+0xa1/0x450 Apr 23 10:07:43 surprise kernel: cpuidle_enter+0x2e/0x40 Apr 23 10:07:43 surprise kernel: call_cpuidle+0x23/0x40 Apr 23 10:07:43 surprise kernel: do_idle+0x1dd/0x270 Apr 23 10:07:43 surprise kernel: cpu_startup_entry+0x20/0x30 Apr 23 10:07:43 surprise kernel: start_secondary+0x167/0x1c0 Apr 23 10:07:43 surprise kernel: secondary_startup_64+0xa4/0xb0 Apr 23 10:07:43 surprise kernel: ---[ end trace cf93a9794ecfd126 ]--- ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-generic 5.4.0.26.32 ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30 Uname: Linux 5.4.0-26-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia ApportVersion: 2.20.11-0ubuntu27 Architecture: amd64 CasperMD5CheckResult: skip CurrentDesktop: i3 Date: Thu Apr 23 10:38:05 2020 InstallationDate: Installed on 2019-05-07 (351 days ago) InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210) MachineType: Gigabyte Technology Co., Ltd. B450M DS3H ProcFB: 0 EFI VGA ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-26-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash resume=UUID=73909634-a75d-42c9-8f66-a69138690756 vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-5.4.0-26-generic N/A linux-backports-modules-5.4.0-26-generic N/A linux-firmware 1.187 RfKill: SourcePackage: linux UpgradeStatus: Upgraded to focal on 2019-11-15 (159 days ago) dmi.bios.date: 01/25/2019 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: F4 dmi.board.asset.tag: Default string dmi.board.name: B450M DS3H-CF dmi.board.vendor: Gigabyte Technology Co., Ltd. dmi.board.version: x.x dmi.chassis.asset.tag: Default string dmi.chassis.type: 3 dmi.chassis.vendor: Default string dmi.chassis.version: Default string dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF4:bd01/25/2019:svnGigabyteTechnologyCo.,Ltd.:pnB450MDS3H:pvrDefaultstring:rvnGigabyteTechnologyCo.,Ltd.:rnB450MDS3H-CF:rvrx.x:cvnDefaultstring:ct3:cvrDefaultstring: dmi.product.family: Default string dmi.product.name: B450M DS3H dmi.product.sku: Default string dmi.product.version: Default string dmi.sys.vendor: Gigabyte Technology Co., Ltd. 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