5.14-rc5: UBSAN: object-size-mismatch in ./include/net/flow.h:197:33

Dear kernel network developers,

It is my first time to see UBSAN from kernel, so I do not know how and where to
report it. I hope here is the right place. I self-build linux 5.14rc5 (the plain upstream
kernel) and run it on Rapsberry Pi4B. Then I got the following UBSAN warnings:

[  185.641264] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  185.648154] member access within address 00000000243f3831 with insufficient space
[  185.655960] for an object of type 'struct flowi'
[  185.660727] CPU: 0 PID: 561 Comm: systemd-resolve Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  185.671073] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  185.677049] Call trace:
[  185.679553]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  185.687862]  dump_stack_lvl+0x8c/0x128
[  185.691708]  dump_stack+0x18/0x24
[  185.695106]  ubsan_type_mismatch_common+0x198/0x2a4
[  185.700106]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  185.705371]  udp_sendmsg+0x9c4/0x115c
[  185.709126]  inet_sendmsg+0x64/0xac
[  185.712701]  ____sys_sendmsg+0x264/0x3b0
[  185.716723]  __sys_sendmsg+0x128/0x198
[  185.720565]  __arm64_sys_sendmsg+0x2c/0x38
[  185.724764]  invoke_syscall+0xac/0x160
[  185.728606]  el0_svc_common+0x98/0x104
[  185.732447]  do_el0_svc+0x30/0x7c
[  185.735843]  el0_svc+0x34/0x128
[  185.739063]  el0t_64_sync_handler+0x6c/0xb0
[  185.743350]  el0t_64_sync+0x150/0x154
[  185.747295] ================================================================================
[  185.756145] ================================================================================
[  185.756157] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  185.756168] member access within address 00000000243f3831 with insufficient space
[  185.756176] for an object of type 'union (anonymous union at ./include/net/flow.h:172:2)'
[  185.756182] CPU: 0 PID: 561 Comm: systemd-resolve Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  185.756191] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  185.756197] Call trace:
[  185.756201]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  185.756222]  dump_stack_lvl+0x8c/0x128
[  185.756233]  dump_stack+0x18/0x24
[  185.756240]  ubsan_type_mismatch_common+0x198/0x2a4
[  185.826926]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  185.832195]  udp_sendmsg+0x9d4/0x115c
[  185.835951]  inet_sendmsg+0x64/0xac
[  185.839526]  ____sys_sendmsg+0x264/0x3b0
[  185.843548]  __sys_sendmsg+0x128/0x198
[  185.847390]  __arm64_sys_sendmsg+0x2c/0x38
[  185.851588]  invoke_syscall+0xac/0x160
[  185.855431]  el0_svc_common+0x98/0x104
[  185.859272]  do_el0_svc+0x30/0x7c
[  185.862668]  el0_svc+0x34/0x128
[  185.865888]  el0t_64_sync_handler+0x6c/0xb0
[  185.870175]  el0t_64_sync+0x150/0x154
[  185.875201] ================================================================================
[  185.884561] ================================================================================
[  185.893845] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  185.900566] member access within address 000000007d6cb106 with insufficient space
[  185.908302] for an object of type 'struct flowi'
[  185.913139] CPU: 0 PID: 530 Comm: irq/61-eth0 Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  185.923143] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  185.929122] Call trace:
[  185.931632]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  185.939954]  dump_stack_lvl+0x8c/0x128
[  185.943816]  dump_stack+0x18/0x24
[  185.947235]  ubsan_type_mismatch_common+0x198/0x2a4
[  185.952246]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  185.957523]  ip_send_unicast_reply+0x240/0x594
[  185.962084]  tcp_v4_send_reset+0x5a8/0x768
[  185.966285]  tcp_v4_rcv+0xf38/0x13d0
[  185.969950]  ip_protocol_deliver_rcu+0x148/0x2fc
[  185.974682]  ip_local_deliver_finish+0x88/0xe8
[  185.979235]  ip_local_deliver+0x1b4/0x23c
[  185.983342]  ip_sublist_rcv_finish+0x9c/0xe8
[  185.987717]  ip_sublist_rcv+0x224/0x308
[  185.991646]  ip_list_rcv+0x120/0x164
[  185.995308]  __netif_receive_skb_list_core+0x230/0x324
[  186.000576]  __netif_receive_skb_list+0x194/0x230
[  186.005397]  netif_receive_skb_list_internal+0x128/0x204
[  186.010841]  napi_complete_done+0xcc/0x1fc
[  186.015040]  bcmgenet_rx_poll+0x5c/0x124
[  186.019062]  __napi_poll+0x60/0x1f8
[  186.022638]  net_rx_action+0x198/0x468
[  186.026481]  __do_softirq+0x16c/0x42c
[  186.030235]  do_softirq+0xcc/0x134
[  186.033723]  __local_bh_enable_ip+0xc8/0x100
[  186.038099]  local_bh_enable.6846+0x14/0x20
[  186.042388]  irq_forced_thread_fn+0x9c/0xf0
[  186.046676]  irq_thread+0x26c/0x4b8
[  186.050251]  kthread+0x2c8/0x338
[  186.053559]  ret_from_fork+0x10/0x18
[  186.057311] ================================================================================
[  186.066065] ================================================================================
[  186.074780] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  186.081499] member access within address 000000007d6cb106 with insufficient space
[  186.089242] for an object of type 'union (anonymous union at ./include/net/flow.h:172:2)'
[  186.097700] CPU: 0 PID: 530 Comm: irq/61-eth0 Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  186.107696] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  186.113672] Call trace:
[  186.116176]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  186.124482]  dump_stack_lvl+0x8c/0x128
[  186.128328]  dump_stack+0x18/0x24
[  186.131727]  ubsan_type_mismatch_common+0x198/0x2a4
[  186.136726]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  186.141991]  ip_send_unicast_reply+0x250/0x594
[  186.146546]  tcp_v4_send_reset+0x5a8/0x768
[  186.150747]  tcp_v4_rcv+0xf38/0x13d0
[  186.154411]  ip_protocol_deliver_rcu+0x148/0x2fc
[  186.159143]  ip_local_deliver_finish+0x88/0xe8
[  186.163696]  ip_local_deliver+0x1b4/0x23c
[  186.167803]  ip_sublist_rcv_finish+0x9c/0xe8
[  186.172178]  ip_sublist_rcv+0x224/0x308
[  186.176107]  ip_list_rcv+0x120/0x164
[  186.179770]  __netif_receive_skb_list_core+0x230/0x324
[  186.185040]  __netif_receive_skb_list+0x194/0x230
[  186.189863]  netif_receive_skb_list_internal+0x128/0x204
[  186.195307]  napi_complete_done+0xcc/0x1fc
[  186.199505]  bcmgenet_rx_poll+0x5c/0x124
[  186.203527]  __napi_poll+0x60/0x1f8
[  186.207103]  net_rx_action+0x198/0x468
[  186.210947]  __do_softirq+0x16c/0x42c
[  186.214700]  do_softirq+0xcc/0x134
[  186.218187]  __local_bh_enable_ip+0xc8/0x100
[  186.222562]  local_bh_enable.6846+0x14/0x20
[  186.226851]  irq_forced_thread_fn+0x9c/0xf0
[  186.231139]  irq_thread+0x26c/0x4b8
[  186.234713]  kthread+0x2c8/0x338
[  186.238021]  ret_from_fork+0x10/0x18
[  186.241759] ================================================================================
[  186.364567] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.371715] ================================================================================
[  186.380601] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  186.380617] member access within address 000000009aa2bab1 with insufficient space
[  186.380625] for an object of type 'struct flowi'
[  186.380632] CPU: 0 PID: 530 Comm: irq/61-eth0 Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  186.409713] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  186.415691] Call trace:
[  186.418196]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  186.426504]  dump_stack_lvl+0x8c/0x128
[  186.430351]  dump_stack+0x18/0x24
[  186.433748]  ubsan_type_mismatch_common+0x198/0x2a4
[  186.438747]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  186.444014]  __icmp_send+0x558/0xef0
[  186.447680]  ipv4_link_failure+0x134/0x214
[  186.451878]  ip6_tnl_xmit+0x96c/0x1190
[  186.455720]  ip6_tnl_start_xmit+0x4c4/0x52c
[  186.460006]  dev_hard_start_xmit+0x128/0x220
[  186.464383]  __dev_queue_xmit+0x6ac/0xd38
[  186.468491]  neigh_connected_output+0x13c/0x188
[  186.473133]  ip_finish_output2+0x300/0x860
[  186.477331]  __ip_finish_output+0x10c/0x1e8
[  186.481617]  ip_finish_output+0x58/0x124
[  186.485636]  ip_output+0x138/0x3f8
[  186.489120]  ip_forward_finish+0xd4/0x140
[  186.493227]  NF_HOOK+0x4c/0x220
[  186.496444]  ip_forward+0x42c/0x594
[  186.500018]  ip_sublist_rcv_finish+0x9c/0xe8
[  186.504392]  ip_sublist_rcv+0x1d4/0x308
[  186.508321]  ip_list_rcv+0x120/0x164
[  186.511984]  __netif_receive_skb_list_core+0x230/0x324
[  186.517252]  __netif_receive_skb_list+0x194/0x230
[  186.522073]  netif_receive_skb_list_internal+0x128/0x204
[  186.527518]  napi_gro_receive+0x108/0x174
[  186.531625]  bcmgenet_desc_rx+0x2bc/0x57c
[  186.535735]  bcmgenet_rx_poll+0x44/0x124
[  186.539753]  __napi_poll+0x60/0x1f8
[  186.543328]  net_rx_action+0x198/0x468
[  186.547170]  __do_softirq+0x16c/0x42c
[  186.550923]  do_softirq+0xcc/0x134
[  186.554410]  __local_bh_enable_ip+0xc8/0x100
[  186.558786]  local_bh_enable.6846+0x14/0x20
[  186.563074]  irq_forced_thread_fn+0x9c/0xf0
[  186.567360]  irq_thread+0x26c/0x4b8
[  186.570935]  kthread+0x2c8/0x338
[  186.574242]  ret_from_fork+0x10/0x18
[  186.578057] ================================================================================
[  186.586818] ================================================================================
[  186.595551] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  186.602325] member access within address 000000009aa2bab1 with insufficient space
[  186.610009] for an object of type 'union (anonymous union at ./include/net/flow.h:172:2)'
[  186.618533] CPU: 0 PID: 530 Comm: irq/61-eth0 Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  186.628541] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  186.634520] Call trace:
[  186.637025]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  186.645331]  dump_stack_lvl+0x8c/0x128
[  186.649177]  dump_stack+0x18/0x24
[  186.652574]  ubsan_type_mismatch_common+0x198/0x2a4
[  186.657572]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  186.662837]  __icmp_send+0x568/0xef0
[  186.666504]  ipv4_link_failure+0x134/0x214
[  186.670703]  ip6_tnl_xmit+0x96c/0x1190
[  186.674546]  ip6_tnl_start_xmit+0x4c4/0x52c
[  186.678833]  dev_hard_start_xmit+0x128/0x220
[  186.683209]  __dev_queue_xmit+0x6ac/0xd38
[  186.687316]  neigh_connected_output+0x13c/0x188
[  186.691959]  ip_finish_output2+0x300/0x860
[  186.696157]  __ip_finish_output+0x10c/0x1e8
[  186.700442]  ip_finish_output+0x58/0x124
[  186.704460]  ip_output+0x138/0x3f8
[  186.707944]  ip_forward_finish+0xd4/0x140
[  186.712052]  NF_HOOK+0x4c/0x220
[  186.715270]  ip_forward+0x42c/0x594
[  186.718843]  ip_sublist_rcv_finish+0x9c/0xe8
[  186.723217]  ip_sublist_rcv+0x1d4/0x308
[  186.727146]  ip_list_rcv+0x120/0x164
[  186.730809]  __netif_receive_skb_list_core+0x230/0x324
[  186.736077]  __netif_receive_skb_list+0x194/0x230
[  186.740897]  netif_receive_skb_list_internal+0x128/0x204
[  186.746341]  napi_gro_receive+0x108/0x174
[  186.750449]  bcmgenet_desc_rx+0x2bc/0x57c
[  186.754560]  bcmgenet_rx_poll+0x44/0x124
[  186.758578]  __napi_poll+0x60/0x1f8
[  186.762153]  net_rx_action+0x198/0x468
[  186.765996]  __do_softirq+0x16c/0x42c
[  186.769749]  do_softirq+0xcc/0x134
[  186.773237]  __local_bh_enable_ip+0xc8/0x100
[  186.777613]  local_bh_enable.6846+0x14/0x20
[  186.781900]  irq_forced_thread_fn+0x9c/0xf0
[  186.786186]  irq_thread+0x26c/0x4b8
[  186.789762]  kthread+0x2c8/0x338
[  186.793069]  ret_from_fork+0x10/0x18
[  186.796834] ================================================================================
[  186.806158] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.813226] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.820129] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.827147] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.834169] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.841261] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.861709] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.868926] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.875970] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.883110] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  186.890356] ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
[  195.356055] ================================================================================
[  195.366929] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  195.374201] member access within address 00000000e8d7399a with insufficient space
[  195.382292] for an object of type 'struct flowi'
[  195.387599] CPU: 3 PID: 1080 Comm: pinger Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  195.397260] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  195.403244] Call trace:
[  195.405753]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  195.414079]  dump_stack_lvl+0x8c/0x128
[  195.417936]  dump_stack+0x18/0x24
[  195.421342]  ubsan_type_mismatch_common+0x198/0x2a4
[  195.426349]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  195.431624]  raw_sendmsg+0x624/0xdbc
[  195.435295]  inet_sendmsg+0x64/0xac
[  195.438879]  __sys_sendto+0x228/0x2d0
[  195.442641]  __arm64_sys_sendto+0x30/0x40
[  195.446764]  invoke_syscall+0xac/0x160
[  195.450618]  el0_svc_common+0xc8/0x104
[  195.454469]  do_el0_svc+0x30/0x7c
[  195.457877]  el0_svc+0x34/0x128
[  195.461109]  el0t_64_sync_handler+0x6c/0xb0
[  195.465406]  el0t_64_sync+0x150/0x154
[  195.483933] ================================================================================
[  195.493442] ================================================================================
[  195.509524] UBSAN: object-size-mismatch in ./include/net/flow.h:197:33
[  195.519422] member access within address 00000000e8d7399a with insufficient space
[  195.528782] for an object of type 'union (anonymous union at ./include/net/flow.h:172:2)'
[  195.539450] CPU: 3 PID: 1080 Comm: pinger Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  195.549107] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  195.555092] Call trace:
[  195.557604]  __typeid__ZTSFiP11task_structPK11user_regsetjjPKvS5_E_global_addr+0x30/0x38
[  195.565920]  dump_stack_lvl+0x8c/0x128
[  195.569775]  dump_stack+0x18/0x24
[  195.573184]  ubsan_type_mismatch_common+0x198/0x2a4
[  195.578196]  __ubsan_handle_type_mismatch_v1+0x40/0x50
[  195.583474]  raw_sendmsg+0x634/0xdbc
[  195.587151]  inet_sendmsg+0x64/0xac
[  195.590736]  __sys_sendto+0x228/0x2d0
[  195.594501]  __arm64_sys_sendto+0x30/0x40
[  195.598618]  invoke_syscall+0xac/0x160
[  195.602471]  el0_svc_common+0xc8/0x104
[  195.606321]  do_el0_svc+0x30/0x7c
[  195.609727]  el0_svc+0x34/0x128
[  195.612959]  el0t_64_sync_handler+0x6c/0xb0
[  195.617258]  el0t_64_sync+0x150/0x154
[  195.628942] ================================================================================
[  613.441480] ------------[ cut here ]------------
[  613.446247] WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:652 rcu_eqs_enter+0xe0/0x130
[  613.454207] Modules linked in: hci_uart btqca btrtl btintel binfmt_misc btsdio btbcm bluetooth sha512_generic nls_ascii nls_cp437 vfat fat sha512_arm64 aes_neon_bs bcm2835_v4l2(C) snd_usb_audio aes_neon_blk evdev crypto_simd cryptd bcm2835_mmal_vchiq(C) snd_soc_core uvcvideo nft_nat snd_usbmidi_lib videobuf2_vmalloc snd_hwdep snd_pcm_dmaengine snd_rawmidi videobuf2_memops cec snd_seq_device drbg drm_kms_helper videobuf2_v4l2 brcmfmac snd_pcm aes_arm64 videobuf2_common snd_timer aes_generic brcmutil ansi_cprng nft_numgen snd videodev ecdh_generic cfg80211 sysimgblt sg soundcore ecc mc syscopyarea crct10dif_ce rfkill libaes vchiq(C) sysfillrect bcm2711_thermal pwm_bcm2835 bcm2835_wdt fb_sys_fops nvmem_rmem leds_gpio cpufreq_dt nft_chain_nat nf_nat nft_reject_inet nf_reject_ipv6 nft_ct nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nft_reject_ipv4 nf_reject_ipv4 nft_reject nft_counter nft_log pkcs8_key_parser cpufreq_powersave vhost_net nf_tables vhost vhost_iotlb nfnetlink tun loop drm fuse
[  613.454683]  drm_panel_orientation_quirks cpufreq_conservative configfs ip_tables x_tables autofs4 uas usb_storage raid6_pq xor xor_neon zstd_compress libcrc32c kyber_iosched dwc2 roles xhci_pci udc_core xhci_hcd sdhci_iproc iproc_rng200 sdhci_pltfm raspberrypi_hwmon i2c_bcm2835 rng_core usbcore fixed gpio_regulator sdhci phy_generic
[  613.574485] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G         C        5.14.0-rc5-clang12almostdebian #1
[  613.584115] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[  613.590092] pstate: 204000c5 (nzCv daIF +PAN -UAO -TCO BTYPE=--)
[  613.596248] pc : rcu_eqs_enter+0xe0/0x130
[  613.600361] lr : rcu_eqs_enter+0x18/0x130
[  613.604471] sp : ffffbca1a19c3d50
[  613.607866] x29: ffffbca1a19c3d60 x28: 000000000162343c x27: d3f3d18400200200
[  613.615194] x26: 3d8fdb8200000000 x25: ffffbca1a209ce20 x24: ffffbca1a19d0000
[  613.622520] x23: ffffbca1a19d0c90 x22: 0000000000000001 x21: 0000000000000000
[  613.629846] x20: ffffbca1a19aecc0 x19: ffff2e80f684fcc0 x18: ffffbca1a19dc2f8
[  613.637170] x17: 00000007fffffff8 x16: 0000000000000028 x15: 0000000000001c00
[  613.644495] x14: 000000afd546f180 x13: ffff2e8064dfda00 x12: 0000000000000039
[  613.651821] x11: 000000001284bb43 x10: 0000000000000001 x9 : 4000000000000000
[  613.659146] x8 : 4000000000000002 x7 : 0000000000000000 x6 : ffffbca1a0023fe0
[  613.666471] x5 : 0000000000000000 x4 : 0000000000000080 x3 : 0000000000000002
[  613.673797] x2 : 0000000000000000 x1 : ffffbca1a1467d7c x0 : 0000000000000000
[  613.681123] Call trace:
[  613.683629]  rcu_eqs_enter+0xe0/0x130
[  613.687383]  default_idle_call+0x38/0xc0
[  613.691405]  do_idle+0x194/0x290
[  613.694716]  cpu_startup_entry+0x2c/0x30
[  613.698736]  kernel_init+0x0/0x2c4
[  613.702224]  start_kernel+0x0/0x554
[  613.705800]  start_kernel+0x4b0/0x554
[  613.709552]  __primary_switched+0xc0/0xc8
[  613.713664] ---[ end trace c515acfca8f78c9a ]---

"ip l" looks as follows:
# ip l
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc pfifo_head_drop state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_head_drop state UP mode DEFAULT group default qlen 1000
    link/ether dc:a6:32:bb:99:d9 brd ff:ff:ff:ff:ff:ff
3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DORMANT group default qlen 1000
    link/ether dc:a6:32:bb:99:da brd ff:ff:ff:ff:ff:ff
4: myve1@eth0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 96:8a:a9:8d:f6:64 brd ff:ff:ff:ff:ff:ff
5: myvtap1@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 500
    link/ether 8e:7e:4b:95:3b:59 brd ff:ff:ff:ff:ff:ff
6: ip6tnl1@myve1: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1460 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/tunnel6 2400:4050:2ba1:ac00:99:f0ae:8600:2c00 peer 2001:380:a120::9 permaddr aa1d:2abe:41ac::

"ip a" looks as follows:
# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc pfifo_head_drop state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_head_drop state UP group default qlen 1000
    link/ether dc:a6:32:bb:99:d9 brd ff:ff:ff:ff:ff:ff
3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether dc:a6:32:bb:99:da brd ff:ff:ff:ff:ff:ff
4: myve1@eth0: <BROADCAST,MULTICAST,ALLMULTI,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 96:8a:a9:8d:f6:64 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.2/24 brd 192.168.1.255 scope global myve1
       valid_lft forever preferred_lft forever
    inet6 2400:4050:2ba1:ac00:948a:a9ff:fe8d:f664/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 13193sec preferred_lft 11393sec
    inet6 2400:4050:2ba1:ac00:99:f0ae:8600:beef/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 2400:4050:2ba1:ac00:99:f0ae:8600:9595/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 2400:4050:2ba1:ac00:99:f0ae:8600:2c00/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::948a:a9ff:fe8d:f664/64 scope link 
       valid_lft forever preferred_lft forever
5: myvtap1@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 500
    link/ether 8e:7e:4b:95:3b:59 brd ff:ff:ff:ff:ff:ff
6: ip6tnl1@myve1: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1460 qdisc noqueue state UNKNOWN group default qlen 1000
    link/tunnel6 2400:4050:2ba1:ac00:99:f0ae:8600:2c00 peer 2001:380:a120::9 permaddr aa1d:2abe:41ac::
    inet 153.240.174.134/32 scope global ip6tnl1
       valid_lft forever preferred_lft forever

The network IFs are configured only by the systemd-networkd.
ip6tnl1 is used for "MAP-E" in the sense of
https://en.wikipedia.org/wiki/Mapping_of_Address_and_Port
which uses nftables.

Full dmesg, kernel build config, nftables.conf,
and systemd-network config files are attached.

I hope this report is somewhat useful for the development.
I will be absent from email for the next 36 hours.

Best regards, Ryutaroh Matsumoto