block nbd0: NBD_DISCONNECT
kasan: CONFIG_KASAN_INLINE enabled
nbd: nbd0 already in use
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 25085 Comm: systemd-udevd Not tainted 4.14.304-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
task: ffff8880972e41c0 task.stack: ffff888088a78000
RIP: 0010:__lock_acquire+0x1cc/0x3f20 kernel/locking/lockdep.c:3369
RSP: 0018:ffff888088a7f938 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000022 RSI: 0000000000000000 RDI: 0000000000000110
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffff8880972e41c0 R12: 0000000000000110
R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8bed0dc0
FS:  00007f8ae70c08c0(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffccc7c9b47 CR3: 000000009c557000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
 flush_workqueue+0xfa/0x1310 kernel/workqueue.c:2625
 nbd_disconnect_and_put+0xc3/0x140 drivers/block/nbd.c:1919
 nbd_release+0x123/0x150 drivers/block/nbd.c:1450
 __blkdev_put+0x5aa/0x800 fs/block_dev.c:1803
 blkdev_close+0x86/0xb0 fs/block_dev.c:1875
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3
RIP: 0033:0x7f8ae6206270
RSP: 002b:00007ffccc7cb6c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 00007f8ae6206270
RDX: 000000000aba9500 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 00007f8ae70c0710 R08: 000055984a02cd30 R09: 0000000000000018
R10: 000055984a02e838 R11: 0000000000000246 R12: 0000000000000000
R13: 000055984a02e380 R14: 0000000000000003 R15: 000000000000000e
Code: 18 00 00 00 00 48 81 c4 80 01 00 00 44 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 b8 00 00 00 00 00 fc ff df 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 67 2a 00 00 49 81 3c 24 e0 c7 2f 8b 0f 84 5f 
RIP: __lock_acquire+0x1cc/0x3f20 kernel/locking/lockdep.c:3369 RSP: ffff888088a7f938
---[ end trace d9550adfc98bc8fd ]---
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	00 00                	add    %al,(%rax)
   2:	00 00                	add    %al,(%rax)
   4:	48 81 c4 80 01 00 00 	add    $0x180,%rsp
   b:	44 89 e8             	mov    %r13d,%eax
   e:	5b                   	pop    %rbx
   f:	5d                   	pop    %rbp
  10:	41 5c                	pop    %r12
  12:	41 5d                	pop    %r13
  14:	41 5e                	pop    %r14
  16:	41 5f                	pop    %r15
  18:	c3                   	retq
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	4c 89 e2             	mov    %r12,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 67 2a 00 00    	jne    0x2a9b
  34:	49 81 3c 24 e0 c7 2f 	cmpq   $0xffffffff8b2fc7e0,(%r12)
  3b:	8b
  3c:	0f                   	.byte 0xf
  3d:	84                   	.byte 0x84
  3e:	5f                   	pop    %rdi