vhci_hcd: connection closed
vhci_hcd vhci_hcd.0: devid(0) speed(3) speed_str(high-speed)
vhci_hcd vhci_hcd.0: port 1 already used
vhci_hcd vhci_hcd.0: pdev(0) rhport(1) sockfd(3)
vhci_hcd vhci_hcd.0: devid(0) speed(3) speed_str(high-speed)
BUG: unable to handle kernel NULL pointer dereference at 000000000000001c
IP: atomic_inc syzkaller/managers/linux-4-14/kernel/./arch/x86/include/asm/atomic.h:92 [inline]
IP: kthread_stop+0x47/0x640 syzkaller/managers/linux-4-14/kernel/kernel/kthread.c:525
PGD 9b4a8067 P4D 9b4a8067 PUD 9b445067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 22 Comm: kworker/u4:1 Not tainted 4.14.218-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 syzkaller/managers/linux-4-14/kernel/./arch/x86/include/asm/atomic.h:92 [inline]
RIP: 0010:kthread_stop+0x47/0x640 syzkaller/managers/linux-4-14/kernel/kernel/kthread.c:525
RSP: 0018:ffff8880b55ffc70 EFLAGS: 00010297
RAX: ffff8880b55ee5c0 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000282
RBP: fffffffffffffffc R08: ffffffff8b9b9578 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880aa3bccd8
R13: ffff8880aa3bccc8 R14: fffffbfff1924128 R15: ffffffff898581a0
FS:  0000000000000000(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000001c CR3: 000000009e938000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 vhci_shutdown_connection+0x12a/0x240 syzkaller/managers/linux-4-14/kernel/drivers/usb/usbip/vhci_hcd.c:1037
 event_handler+0x1c3/0x4a0 syzkaller/managers/linux-4-14/kernel/drivers/usb/usbip/usbip_event.c:92
 process_one_work+0x793/0x14a0 syzkaller/managers/linux-4-14/kernel/kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 syzkaller/managers/linux-4-14/kernel/kernel/workqueue.c:2250
 kthread+0x30d/0x420 syzkaller/managers/linux-4-14/kernel/kernel/kthread.c:232
 ret_from_fork+0x24/0x30 syzkaller/managers/linux-4-14/kernel/arch/x86/entry/entry_64.S:404
Code: 00 65 8b 1d 6c 2b ca 7e 83 fb 07 0f 87 5b 04 00 00 e8 ce c8 1d 00 89 db 48 0f a3 1d fc 5f d1 08 0f 82 a2 03 00 00 e8 b9 c8 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 syzkaller/managers/linux-4-14/kernel/./arch/x86/include/asm/atomic.h:92 [inline] RSP: ffff8880b55ffc70
RIP: kthread_stop+0x47/0x640 syzkaller/managers/linux-4-14/kernel/kernel/kthread.c:525 RSP: ffff8880b55ffc70
CR2: 000000000000001c
---[ end trace a0e2e5e10346c701 ]---