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: 8503 Comm: syz.9.219 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:984
 register_lock_class+0xcc/0x2e0 kernel/locking/lockdep.c:1299
 __lock_acquire+0xab/0x2cf0 kernel/locking/lockdep.c:5112
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
 spin_lock include/linux/spinlock.h:342 [inline]
 nfsd4_cancel_copy_by_sb+0x10d/0x840 fs/nfsd/nfs4proc.c:1574
 write_unlock_fs+0x286/0x440 fs/nfsd/nfsctl.c:299
 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112
 vfs_write+0x296/0xba0 fs/read_write.c:685
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcee779e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcee85a4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fcee7a26360 RCX: 00007fcee779e019
RDX: 0000000000000001 RSI: 0000200000000640 RDI: 0000000000000007
RBP: 00007fcee783500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcee7a263f8 R14: 00007fcee7a26360 R15: 00007ffd40ca8bc8
 </TASK>
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 8503 Comm: syz.9.219 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:nfsd4_cancel_copy_by_sb+0x161/0x840 fs/nfsd/nfs4proc.c:1578
Code: 48 42 80 3c 31 00 74 0f 48 8b 7c 24 10 e8 a7 ad 4c ff 48 8b 44 24 10 48 8b 5c 24 18 48 c1 e3 04 48 03 18 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 80 ad 4c ff 48 8b 03 48 39 d8 48
RSP: 0018:ffffc90003e8fa80 EFLAGS: 00010256
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff1100b8b780d
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90003e8fa00
RBP: ffffc90003e8fb70 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520007d1f40 R12: ffffc90003e8fb00
R13: ffff88806993b820 R14: dffffc0000000000 R15: 1ffff920007d1f5c
FS:  00007fcee85a46c0(0000) GS:ffff888124f4b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcee85a3ff8 CR3: 0000000031a63000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 write_unlock_fs+0x286/0x440 fs/nfsd/nfsctl.c:299
 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:112
 vfs_write+0x296/0xba0 fs/read_write.c:685
 ksys_write+0x150/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcee779e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcee85a4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fcee7a26360 RCX: 00007fcee779e019
RDX: 0000000000000001 RSI: 0000200000000640 RDI: 0000000000000007
RBP: 00007fcee783500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcee7a263f8 R14: 00007fcee7a26360 R15: 00007ffd40ca8bc8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nfsd4_cancel_copy_by_sb+0x161/0x840 fs/nfsd/nfs4proc.c:1578
Code: 48 42 80 3c 31 00 74 0f 48 8b 7c 24 10 e8 a7 ad 4c ff 48 8b 44 24 10 48 8b 5c 24 18 48 c1 e3 04 48 03 18 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 80 ad 4c ff 48 8b 03 48 39 d8 48
RSP: 0018:ffffc90003e8fa80 EFLAGS: 00010256
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff1100b8b780d
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90003e8fa00
RBP: ffffc90003e8fb70 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520007d1f40 R12: ffffc90003e8fb00
R13: ffff88806993b820 R14: dffffc0000000000 R15: 1ffff920007d1f5c
FS:  00007fcee85a46c0(0000) GS:ffff888124f4b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcee85a3ff8 CR3: 0000000031a63000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	48                   	rex.W
   1:	42 80 3c 31 00       	cmpb   $0x0,(%rcx,%r14,1)
   6:	74 0f                	je     0x17
   8:	48 8b 7c 24 10       	mov    0x10(%rsp),%rdi
   d:	e8 a7 ad 4c ff       	call   0xff4cadb9
  12:	48 8b 44 24 10       	mov    0x10(%rsp),%rax
  17:	48 8b 5c 24 18       	mov    0x18(%rsp),%rbx
  1c:	48 c1 e3 04          	shl    $0x4,%rbx
  20:	48 03 18             	add    (%rax),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 30 00       	cmpb   $0x0,(%rax,%r14,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 80 ad 4c ff       	call   0xff4cadb9
  39:	48 8b 03             	mov    (%rbx),%rax
  3c:	48 39 d8             	cmp    %rbx,%rax
  3f:	48                   	rex.W