INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 0 UID: 0 PID: 8107 Comm: nfsd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 assign_lock_key+0x133/0x150
 register_lock_class+0xcc/0x2e0
 __lock_acquire+0xaf/0x2e50
 lock_acquire+0x115/0x350
 _raw_spin_lock+0x2e/0x40
 nfsd_file_net_dispose+0xff/0x450
 nfsd+0x2ed/0xbb0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 8107 Comm: nfsd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:__list_del_entry_valid_or_report+0x25/0x190
Code: 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 89 fb 49 bd 00 00 00 00 00 fc ff df 48 83 c7 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 8f f2 4d fd 4c 8b 7b 08 48 89 d8 48 c1 e8
RSP: 0018:ffffc9000371fbd0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000008
RBP: ffffc9000371fcd0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520006e3f70 R12: ffff88810f962c40
R13: dffffc0000000000 R14: ffffc9000371fc60 R15: 0000000000000007
FS:  0000000000000000(0000) GS:ffff88818d6da000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feacc666ff8 CR3: 00000001b02be000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 nfsd_file_net_dispose+0x132/0x450
 nfsd+0x2ed/0xbb0
 kthread+0x38b/0x480
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0x25/0x190
Code: 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 89 fb 49 bd 00 00 00 00 00 fc ff df 48 83 c7 08 48 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 05 e8 8f f2 4d fd 4c 8b 7b 08 48 89 d8 48 c1 e8
RSP: 0018:ffffc9000371fbd0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000008
RBP: ffffc9000371fcd0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520006e3f70 R12: ffff88810f962c40
R13: dffffc0000000000 R14: ffffc9000371fc60 R15: 0000000000000007
FS:  0000000000000000(0000) GS:ffff88818d6da000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feacc666ff8 CR3: 000000000eb48000 CR4: 00000000000006f0
