syzbot

------------[ cut here ]------------
rtmutex deadlock detected
WARNING: kernel/locking/rtmutex.c:1674 at rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1674, CPU#0: syz.7.2908/15923
Modules linked in:
CPU: 0 UID: 0 PID: 15923 Comm: syz.7.2908 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1674
Code: 90 90 90 90 90 90 90 90 90 41 57 41 56 41 55 41 54 53 83 ff dd 0f 85 86 00 00 00 48 89 f7 e8 a6 39 01 00 48 8d 3d af 7c 0a 04 <67> 48 0f b9 3a 4c 8d 3d 00 00 00 00 65 48 8b 1c 25 08 10 b3 91 4c
RSP: 0018:ffffc90004617710 EFLAGS: 00010286
RAX: 0000000080000000 RBX: ffffc900046177a0 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff8ce0bbf9 RDI: ffffffff8ede5760
RBP: ffffc900046178c0 R08: ffffffff8edb3477 R09: 1ffffffff1db668e
R10: dffffc0000000000 R11: fffffbfff1db668f R12: 1ffff920008c2ef0
R13: ffffffff8ad3d599 R14: ffffffff8eb910e0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888126cef000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056422df5abe0 CR3: 000000005929c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1734 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
 rt_mutex_slowlock+0x666/0x6b0 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
 mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:552
 rfkill_unregister+0xd1/0x230 net/rfkill/core.c:1145
 nfc_unregister_device+0x96/0x300 net/nfc/core.c:1167
 virtual_ncidev_close+0x59/0x90 drivers/nfc/virtual_ncidev.c:172
 __fput+0x45b/0xa80 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x694/0x22f0 kernel/exit.c:971
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x125d/0x1310 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2e7f9af749
Code: Unable to access opcode bytes at 0x7f2e7f9af71f.
RSP: 002b:00007f2e7dc0e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: 0000000000000008 RBX: 00007f2e7fc05fa0 RCX: 00007f2e7f9af749
RDX: 0000000000000002 RSI: 0000200000000500 RDI: ffffffffffffff9c
RBP: 00007f2e7fa33f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2e7fc06038 R14: 00007f2e7fc05fa0 R15: 00007fff5a2e50f8
 </TASK>
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	90                   	nop
   2:	90                   	nop
   3:	90                   	nop
   4:	90                   	nop
   5:	90                   	nop
   6:	90                   	nop
   7:	90                   	nop
   8:	90                   	nop
   9:	41 57                	push   %r15
   b:	41 56                	push   %r14
   d:	41 55                	push   %r13
   f:	41 54                	push   %r12
  11:	53                   	push   %rbx
  12:	83 ff dd             	cmp    $0xffffffdd,%edi
  15:	0f 85 86 00 00 00    	jne    0xa1
  1b:	48 89 f7             	mov    %rsi,%rdi
  1e:	e8 a6 39 01 00       	call   0x139c9
  23:	48 8d 3d af 7c 0a 04 	lea    0x40a7caf(%rip),%rdi        # 0x40a7cd9
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	4c 8d 3d 00 00 00 00 	lea    0x0(%rip),%r15        # 0x36
  36:	65 48 8b 1c 25 08 10 	mov    %gs:0xffffffff91b31008,%rbx
  3d:	b3 91
  3f:	4c                   	rex.WR