syzbot

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workqueue: cannot queue hci_conn_timeout on wq hci4
WARNING: kernel/workqueue.c:2251 at 0x0, CPU#0: syz.0.852/9314
Modules linked in:
CPU: 0 UID: 0 PID: 9314 Comm: syz.0.852 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__queue_work+0xca1/0x10e0 kernel/workqueue.c:2250
Code: 78 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 0c 04 00 00 48 8d 3d 63 3a 06 0f 48 8b 75 18 <67> 48 0f b9 3a e9 90 f7 ff ff e8 e0 31 3a 00 90 0f 0b 90 e9 15 f6
RSP: 0018:ffffc9000dadf7d0 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1100f26b94b
RDX: ffff8880282c8178 RSI: ffffffff8a6e1e50 RDI: ffffffff908aece0
RBP: ffff88807935ca40 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888034310b30 R12: 0000000000000000
R13: ffff8880282c8000 R14: ffff88807935ca88 R15: ffff8880282c8000
FS:  00007fb3d67676c0(0000) GS:ffff888124909000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007c0ff000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __queue_delayed_work+0x35b/0x460 kernel/workqueue.c:2503
 queue_delayed_work_on+0x1b5/0x200 kernel/workqueue.c:2555
 queue_delayed_work include/linux/workqueue.h:684 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1710 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1684 [inline]
 l2cap_chan_del+0x5a0/0x940 net/bluetooth/l2cap_core.c:672
 l2cap_chan_close+0xfe/0xa80 net/bluetooth/l2cap_core.c:845
 l2cap_sock_shutdown+0x3cc/0x11b0 net/bluetooth/l2cap_sock.c:1384
 l2cap_sock_release+0x8d/0x280 net/bluetooth/l2cap_sock.c:1431
 __sock_release+0xb3/0x270 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x402/0xb70 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:233
 get_signal+0x1d0/0x26d0 kernel/signal.c:2807
 arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x8c/0x540 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+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb3d598f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb3d6767038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 00007fb3d5be6180 RCX: 00007fb3d598f749
RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000008
RBP: 00007fb3d5a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb3d5be6218 R14: 00007fb3d5be6180 R15: 00007ffc7c9c6d98
 </TASK>
----------------
Code disassembly (best guess):
   0:	78 01                	js     0x3
   2:	00 00                	add    %al,(%rax)
   4:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
   b:	fc ff df
   e:	48 89 f9             	mov    %rdi,%rcx
  11:	48 c1 e9 03          	shr    $0x3,%rcx
  15:	80 3c 01 00          	cmpb   $0x0,(%rcx,%rax,1)
  19:	0f 85 0c 04 00 00    	jne    0x42b
  1f:	48 8d 3d 63 3a 06 0f 	lea    0xf063a63(%rip),%rdi        # 0xf063a89
  26:	48 8b 75 18          	mov    0x18(%rbp),%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 90 f7 ff ff       	jmp    0xfffff7c4
  34:	e8 e0 31 3a 00       	call   0x3a3219
  39:	90                   	nop
  3a:	0f 0b                	ud2
  3c:	90                   	nop
  3d:	e9                   	.byte 0xe9
  3e:	15                   	.byte 0x15
  3f:	f6                   	.byte 0xf6