IPv6: ADDRCONF(NETDEV_UP): veth1_to_batadv: link is not ready vhci_hcd vhci_hcd.0: pdev(3) rhport(1) sockfd(3) vhci_hcd vhci_hcd.0: devid(0) speed(1) speed_str(low-speed) batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 vhci_hcd: connection closed BUG: unable to handle kernel NULL pointer dereference at 000000000000001c IP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline] IP: kthread_stop+0x47/0x640 kernel/kthread.c:525 PGD 6d3ed067 P4D 6d3ed067 PUD 6d3ee067 PMD 0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! Oops: 0002 [#1] PREEMPT SMP KASAN batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 Modules linked in: batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! CPU: 1 PID: 5434 Comm: kworker/u4:5 Not tainted 4.14.215-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usbip_event event_handler batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 task: ffff8880a9fd4480 task.stack: ffff8880932e8000 RIP: 0010:atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RIP: 0010:kthread_stop+0x47/0x640 kernel/kthread.c:525 RSP: 0018:ffff8880932efc70 EFLAGS: 00010297 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! RAX: ffff8880a9fd4480 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000286 RBP: fffffffffffffffc R08: ffffffff8b9bd9f8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888237d64a18 R13: ffff888237d64a08 R14: fffffbfff1924320 R15: ffffffff898586c0 FS: 0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! CR2: 000000000000001c CR3: 000000006d3ec000 CR4: 00000000001406e0 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vhci_shutdown_connection+0x12a/0x240 drivers/usb/usbip/vhci_hcd.c:1037 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! IPv6: ADDRCONF(NETDEV_UP): batadv_slave_0: link is not ready event_handler+0x1c3/0x4a0 drivers/usb/usbip/usbip_event.c:92 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 batman_adv: batadv0: Interface activated: batadv_slave_0 IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 IPv6: ADDRCONF(NETDEV_CHANGE): macsec0: link becomes ready ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready 00 65 8b 1d cc 15 c9 7e 83 fb 07 0f 87 IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready 5b 04 00 00 e8 1e d6 1e 00 89 db 48 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 0f a3 1d 9c 50 d0 08 0f 82 a2 03 00 00 e8 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! 09 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 d6 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! 1e batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 00 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! <f0> batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 ff 45 20 48 8d 7d 24 48 b8 00 00 00 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! 00 00 fc ff df 48 89 fa RIP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RSP: ffff8880932efc70 RIP: kthread_stop+0x47/0x640 kernel/kthread.c:525 RSP: ffff8880932efc70 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 CR2: 000000000000001c ---[ end trace 3072a113a50075ce ]---