I am building a system which coordinates the meshing of wireguard devices. Currently, all the devices are running on an embedded platform (AMD Geode LX500) and works as expected. However, when introducing a 64bit KVM host for testing, all the 32bit hosts running on the Geode platform, report the following warning and drop offline temporarily. The CPU usage on KVM host spikes and all the CPU time is spent on the kernel threads servicing the WG interfaces. I'm using kernel 4.19.41 and have seen the issue with both the last WG snapshot as well building from master. Is this a bug in WG? May 10 18:36:25 buildroot kern.warn kernel: WARNING: CPU: 0 PID: 9 at kernel/workqueue.c:1442 __queue_work+0x1d4/0x2aa May 10 18:36:25 buildroot kern.warn kernel: CPU: 0 PID: 9 Comm: ksoftirqd/0 Tainted: G W 4.19.41-banana #1 May 10 18:36:25 buildroot kern.warn kernel: EIP: __queue_work+0x1d4/0x2aa May 10 18:36:25 buildroot kern.warn kernel: Code: c1 e8 4e 09 1d 00 c7 05 30 d3 5f c1 00 00 00 00 c7 45 e4 00 00 00 00 e9 76 fe ff ff 8b 3d 80 3c 60 c1 89 78 10 e9 32 ff ff ff <0f> 0b b8 01 00 00 00 e8 1c 82 00 00 a1 a8 9e 5f c1 85 c0 0f 85 3b May 10 18:36:25 buildroot kern.warn kernel: EAX: 00000000 EBX: cfb63044 ECX: 00000003 EDX: cfb63048 May 10 18:36:25 buildroot kern.warn kernel: ESI: cfdfbb00 EDI: cfab29c0 EBP: cf847d38 ESP: cf847d1c May 10 18:36:25 buildroot kern.warn kernel: DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 EFLAGS: 00010086 May 10 18:36:25 buildroot kern.warn kernel: CR0: 80050033 CR2: a7bb5058 CR3: 0eebe000 CR4: 00000090 May 10 18:36:25 buildroot kern.warn kernel: Call Trace: May 10 18:36:25 buildroot kern.warn kernel: queue_work_on+0x19/0x1d May 10 18:36:25 buildroot kern.warn kernel: wg_packet_receive+0x4a5/0x557 May 10 18:36:25 buildroot kern.warn kernel: ? send6+0x1fc/0x1fc May 10 18:36:25 buildroot kern.warn kernel: wg_receive+0x16/0x25 May 10 18:36:25 buildroot kern.warn kernel: udp_queue_rcv_skb+0x254/0x324 May 10 18:36:25 buildroot kern.warn kernel: udp_unicast_rcv_skb.isra.12+0x68/0x7a May 10 18:36:25 buildroot kern.warn kernel: __udp4_lib_rcv+0x413/0x88b May 10 18:36:25 buildroot kern.warn kernel: udp_rcv+0x12/0x14 May 10 18:36:25 buildroot kern.warn kernel: ip_local_deliver_finish+0x82/0x1ff May 10 18:36:25 buildroot kern.warn kernel: ip_local_deliver+0xc0/0xcb May 10 18:36:25 buildroot kern.warn kernel: ? ip_sublist_rcv_finish+0x41/0x41 May 10 18:36:25 buildroot kern.warn kernel: ip_rcv_finish+0x24/0x2a May 10 18:36:25 buildroot kern.warn kernel: ip_rcv+0xa1/0xaf May 10 18:36:25 buildroot kern.warn kernel: ? ip_rcv_finish_core.isra.0+0x331/0x331 May 10 18:36:25 buildroot kern.warn kernel: __netif_receive_skb_one_core+0x3f/0x59 May 10 18:36:25 buildroot kern.warn kernel: __netif_receive_skb+0x16/0x4f May 10 18:36:25 buildroot kern.warn kernel: netif_receive_skb_internal+0x26/0xaf May 10 18:36:25 buildroot kern.warn kernel: netif_receive_skb+0x8/0xa May 10 18:36:25 buildroot kern.warn kernel: rhine_napipoll+0x5ef/0x9c6 May 10 18:36:25 buildroot kern.warn kernel: net_rx_action+0x197/0x24d May 10 18:36:25 buildroot kern.warn kernel: __do_softirq+0xd6/0x1ae May 10 18:36:25 buildroot kern.warn kernel: run_ksoftirqd+0x21/0x24 May 10 18:36:25 buildroot kern.warn kernel: smpboot_thread_fn+0x137/0x1ea May 10 18:36:25 buildroot kern.warn kernel: kthread+0xbe/0xea May 10 18:36:25 buildroot kern.warn kernel: ? sort_range+0x18/0x18 May 10 18:36:25 buildroot kern.warn kernel: ? __kthread_create_on_node+0x13e/0x13e May 10 18:36:25 buildroot kern.warn kernel: ret_from_fork+0x19/0x24 May 10 18:36:25 buildroot kern.warn kernel: ---[ end trace c200a14cd22c0ee1 ]--- May 10 18:36:25 buildroot kern.warn kernel: WARNING: CPU: 0 PID: 9 at kernel/workqueue.c:1442 __queue_work+0x1d4/0x2aa May 10 18:36:25 buildroot kern.warn kernel: CPU: 0 PID: 9 Comm: ksoftirqd/0 Tainted: G W 4.19.41-banana #1 May 10 18:36:25 buildroot kern.warn kernel: EIP: __queue_work+0x1d4/0x2aa May 10 18:36:25 buildroot kern.warn kernel: Code: c1 e8 4e 09 1d 00 c7 05 30 d3 5f c1 00 00 00 00 c7 45 e4 00 00 00 00 e9 76 fe ff ff 8b 3d 80 3c 60 c1 89 78 10 e9 32 ff ff ff <0f> 0b b8 01 00 00 00 e8 1c 82 00 00 a1 a8 9e 5f c1 85 c0 0f 85 3b May 10 18:36:25 buildroot kern.warn kernel: EAX: 00000000 EBX: cfb62044 ECX: 00000003 EDX: cfb62048 May 10 18:36:25 buildroot kern.warn kernel: ESI: cfdfbb00 EDI: cfab29c0 EBP: cf847d38 ESP: cf847d1c May 10 18:36:25 buildroot kern.warn kernel: DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 EFLAGS: 00010086 May 10 18:36:25 buildroot kern.warn kernel: CR0: 80050033 CR2: a7bb5058 CR3: 0eebe000 CR4: 00000090 May 10 18:36:25 buildroot kern.warn kernel: Call Trace: May 10 18:36:25 buildroot kern.warn kernel: queue_work_on+0x19/0x1d May 10 18:36:25 buildroot kern.warn kernel: wg_packet_receive+0x4a5/0x557 May 10 18:36:25 buildroot kern.warn kernel: ? send6+0x1fc/0x1fc May 10 18:36:25 buildroot kern.warn kernel: wg_receive+0x16/0x25 May 10 18:36:25 buildroot kern.warn kernel: udp_queue_rcv_skb+0x254/0x324 May 10 18:36:25 buildroot kern.warn kernel: udp_unicast_rcv_skb.isra.12+0x68/0x7a May 10 18:36:25 buildroot kern.warn kernel: __udp4_lib_rcv+0x413/0x88b May 10 18:36:25 buildroot kern.warn kernel: udp_rcv+0x12/0x14 May 10 18:36:25 buildroot kern.warn kernel: ip_local_deliver_finish+0x82/0x1ff May 10 18:36:25 buildroot kern.warn kernel: ip_local_deliver+0xc0/0xcb May 10 18:36:25 buildroot kern.warn kernel: ? ip_sublist_rcv_finish+0x41/0x41 May 10 18:36:25 buildroot kern.warn kernel: ip_rcv_finish+0x24/0x2a May 10 18:36:25 buildroot kern.warn kernel: ip_rcv+0xa1/0xaf May 10 18:36:25 buildroot kern.warn kernel: ? ip_rcv_finish_core.isra.0+0x331/0x331 May 10 18:36:25 buildroot kern.warn kernel: __netif_receive_skb_one_core+0x3f/0x59 May 10 18:36:25 buildroot kern.warn kernel: __netif_receive_skb+0x16/0x4f May 10 18:36:25 buildroot kern.warn kernel: netif_receive_skb_internal+0x26/0xaf May 10 18:36:25 buildroot kern.warn kernel: netif_receive_skb+0x8/0xa May 10 18:36:25 buildroot kern.warn kernel: rhine_napipoll+0x5ef/0x9c6 May 10 18:36:25 buildroot kern.warn kernel: net_rx_action+0x197/0x24d May 10 18:36:25 buildroot kern.warn kernel: __do_softirq+0xd6/0x1ae May 10 18:36:25 buildroot kern.warn kernel: run_ksoftirqd+0x21/0x24 May 10 18:36:25 buildroot kern.warn kernel: smpboot_thread_fn+0x137/0x1ea May 10 18:36:25 buildroot kern.warn kernel: kthread+0xbe/0xea May 10 18:36:25 buildroot kern.warn kernel: ? sort_range+0x18/0x18 May 10 18:36:25 buildroot kern.warn kernel: ? __kthread_create_on_node+0x13e/0x13e May 10 18:36:25 buildroot kern.warn kernel: ret_from_fork+0x19/0x24 May 10 18:36:25 buildroot kern.warn kernel: ---[ end trace c200a14cd22c0ee2 ]---