------------[ cut here ]------------
ODEBUG: activate active (active state 0) object: ffff888033838dd8 object type: rcu_head hint: 0x0
WARNING: lib/debugobjects.c:632 at debug_print_object lib/debugobjects.c:629 [inline], CPU#0: rcuc/0/20
WARNING: lib/debugobjects.c:632 at debug_object_activate+0x32f/0x520 lib/debugobjects.c:859, CPU#0: rcuc/0/20
Modules linked in:
CPU: 0 UID: 0 PID: 20 Comm: rcuc/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026
RIP: 0010:debug_print_object lib/debugobjects.c:629 [inline]
RIP: 0010:debug_object_activate+0x390/0x520 lib/debugobjects.c:859
Code: 30 00 74 08 4c 89 ef e8 be 91 82 fd 4d 8b 4d 00 4c 89 e7 48 c7 c6 e0 6a a6 8b 4c 89 fa 8b 4c 24 04 4c 8b 44 24 10 ff 74 24 08 <67> 48 0f b9 3a 48 83 c4 08 4c 8b 7c 24 18 ff 05 68 7b c2 0a b8 ea
RSP: 0018:ffffc900001979f0 EFLAGS: 00010246
RAX: 1ffffffff169c36c RBX: ffff888033838dd8 RCX: 0000000000000000
RDX: ffffffff8ba670c0 RSI: ffffffff8ba66ae0 RDI: ffffffff8f747070
RBP: 0000000000000003 R08: ffff888033838dd8 R09: ffffffff8b4e1bc0
R10: dffffc0000000000 R11: 0000000000000000 R12: ffffffff8f747070
R13: ffffffff8b4e1b60 R14: dffffc0000000000 R15: ffffffff8ba670c0
FS:  0000000000000000(0000) GS:ffff88812633c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000003247a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 __call_rcu_common kernel/rcu/tree.c:3116 [inline]
 call_rcu+0x43/0x890 kernel/rcu/tree.c:3251
 radix_tree_node_free lib/radix-tree.c:310 [inline]
 delete_node+0x1bc/0xa60 lib/radix-tree.c:573
 radix_tree_delete_item+0x2ef/0x400 lib/radix-tree.c:1430
 afs_cell_destroy+0x16f/0x2c0 fs/afs/cell.c:580
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core kernel/rcu/tree.c:2869 [inline]
 rcu_cpu_kthread+0x99e/0x1470 kernel/rcu/tree.c:2957
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	30 00                	xor    %al,(%rax)
   2:	74 08                	je     0xc
   4:	4c 89 ef             	mov    %r13,%rdi
   7:	e8 be 91 82 fd       	call   0xfd8291ca
   c:	4d 8b 4d 00          	mov    0x0(%r13),%r9
  10:	4c 89 e7             	mov    %r12,%rdi
  13:	48 c7 c6 e0 6a a6 8b 	mov    $0xffffffff8ba66ae0,%rsi
  1a:	4c 89 fa             	mov    %r15,%rdx
  1d:	8b 4c 24 04          	mov    0x4(%rsp),%ecx
  21:	4c 8b 44 24 10       	mov    0x10(%rsp),%r8
  26:	ff 74 24 08          	push   0x8(%rsp)
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	48 83 c4 08          	add    $0x8,%rsp
  33:	4c 8b 7c 24 18       	mov    0x18(%rsp),%r15
  38:	ff 05 68 7b c2 0a    	incl   0xac27b68(%rip)        # 0xac27ba6
  3e:	b8                   	.byte 0xb8
  3f:	ea                   	(bad)