batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
vhci_hcd: disconnect device
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
vhci_hcd: connection closed
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
BUG: unable to handle kernel NULL pointer dereference at 000000000000001c
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1
IP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline]
IP: kthread_stop+0x47/0x640 kernel/kthread.c:525
PGD b5306067 P4D b5306067 PUD b60cd067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 4.14.217-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usbip_event event_handler
task: ffff8880b55ee5c0 task.stack: ffff8880b55f8000
RIP: 0010:atomic_inc arch/x86/include/asm/atomic.h:92 [inline]
RIP: 0010:kthread_stop+0x47/0x640 kernel/kthread.c:525
RSP: 0018:ffff8880b55ffc70 EFLAGS: 00010297
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
RAX: ffff8880b55ee5c0 RBX: 0000000000000001 RCX: 0000000000000000
IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000282
RBP: fffffffffffffffc R08: ffffffff8b9bd9f8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888237e34a58
R13: ffff888237e34a48 R14: fffffbfff1924328 R15: ffffffff898586c0
batman_adv: batadv0: Interface activated: batadv_slave_1
FS:  0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000001c CR3: 00000000b027e000 CR4: 00000000001406e0
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
 event_handler+0x1c3/0x4a0 drivers/usb/usbip/usbip_event.c:92
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
vhci_hcd vhci_hcd.0: pdev(4) rhport(0) sockfd(3)
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
vhci_hcd vhci_hcd.0: devid(0) speed(1) speed_str(low-speed)
Code: 
vhci_hcd: connection closed
00 65 8b 1d 6c 2b ca 7e 83 fb 07 0f 87 5b 04 00 00 e8 8e cf 1d 00 89 db 48 0f a3 1d fc 64 d1 08 0f 82 a2 03 00 00 e8 79 cf 1d 00 <f0> ff 45 20 48 8d 7d 24 48 b8 00 00 00 00 00 fc ff df 48 89 fa 
RIP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RSP: ffff8880b55ffc70
RIP: kthread_stop+0x47/0x640 kernel/kthread.c:525 RSP: ffff8880b55ffc70
CR2: 000000000000001c
---[ end trace dad726f7b6731dee ]---