INFO: task khidpd_16c04155:5977 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:khidpd_16c04155 state:D stack:28616 pid:5977  ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0xc1/0x2d0 kernel/time/timer.c:2144
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion+0x2c6/0x5a0 kernel/sched/completion.c:148
 __flush_work+0x92f/0xac0 kernel/workqueue.c:3475
 __cancel_work_timer+0x3f8/0x560 kernel/workqueue.c:3562
 hidp_session_remove+0xae/0x2b0 net/bluetooth/hidp/core.c:1198
 l2cap_unregister_user+0x13f/0x160 net/bluetooth/l2cap_core.c:1766
 hidp_session_thread+0x194c/0x19d0 net/bluetooth/hidp/core.c:1334
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
INFO: task syz.3.38:6003 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.38        state:D stack:27560 pid:6003  ppid:5899   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 l2cap_chan_connect+0x7fd/0xe30 net/bluetooth/l2cap_core.c:7318
 l2cap_sock_connect+0x586/0x760 net/bluetooth/l2cap_sock.c:257
 __sys_connect_file net/socket.c:2057 [inline]
 __sys_connect+0x3da/0x470 net/socket.c:2074
 __do_sys_connect net/socket.c:2084 [inline]
 __se_sys_connect net/socket.c:2081 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5b8659e159
RSP: 002b:00007ffc194ec638 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f5b86825fa0 RCX: 00007f5b8659e159
RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f5b8663506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5b86825fac R14: 00007f5b86825fa0 R15: 00007f5b86825fa0
 </TASK>
INFO: task syz.1.39:6005 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.39        state:D stack:27560 pid:6005  ppid:5907   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
 l2cap_sock_connect+0x586/0x760 net/bluetooth/l2cap_sock.c:257
 __sys_connect_file net/socket.c:2057 [inline]
 __sys_connect+0x3da/0x470 net/socket.c:2074
 __do_sys_connect net/socket.c:2084 [inline]
 __se_sys_connect net/socket.c:2081 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f210959e159
RSP: 002b:00007ffd2fefca48 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f2109825fa0 RCX: 00007f210959e159
RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f210963506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2109825fac R14: 00007f2109825fa0 R15: 00007f2109825fa0
 </TASK>
INFO: task syz.2.19:6009 blocked for more than 146 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:26664 pid:6009  ppid:5906   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
 l2cap_sock_connect+0x586/0x760 net/bluetooth/l2cap_sock.c:257
 __sys_connect_file net/socket.c:2057 [inline]
 __sys_connect+0x3da/0x470 net/socket.c:2074
 __do_sys_connect net/socket.c:2084 [inline]
 __se_sys_connect net/socket.c:2081 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5915b9e159
RSP: 002b:00007ffc1184e968 EFLAGS: 00000246
 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f5915e25fa0 RCX: 00007f5915b9e159
RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f5915c3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5915e25fac R14: 00007f5915e25fa0 R15: 00007f5915e25fa0
 </TASK>
INFO: task syz.0.17:6010 blocked for more than 147 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D
 stack:26664 pid:6010  ppid:5900   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6834
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x673/0xc80 kernel/locking/mutex.c:747
 l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
 l2cap_sock_connect+0x586/0x760 net/bluetooth/l2cap_sock.c:257
 __sys_connect_file net/socket.c:2057 [inline]
 __sys_connect+0x3da/0x470 net/socket.c:2074
 __do_sys_connect net/socket.c:2084 [inline]
 __se_sys_connect net/socket.c:2081 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2081
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fcb7ed9e159
RSP: 002b:00007ffc5a96c048 EFLAGS: 00000246
 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fcb7f025fa0 RCX: 00007fcb7ed9e159
RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007fcb7ee3506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb7f025fac R14: 00007fcb7f025fa0 R15: 00007fcb7f025fa0
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/11:
1 lock held by khungtaskd/29:
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6669
4 locks held by kworker/u4:2/33:
3 locks held by kworker/u4:5/60:
3 locks held by kworker/0:2/789:
2 locks held by getty/5533:
 #0: ffff88802d82c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: 
ffffc9000327b2f0
 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217
9 locks held by kworker/0:4/5945:
2 locks held by khidpd_16c04155/5977:
 #0: 
ffff88802166e338
 (&conn->lock#2){+.+.}-{3:3}, at: l2cap_unregister_user+0x35/0x160 net/bluetooth/l2cap_core.c:1760
 #1: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_remove+0x2c/0x2b0 net/bluetooth/hidp/core.c:1185
2 locks held by syz.3.38/6003:
 #0: ffff8880756140b8 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
 #1: ffff88802166e338 (&conn->lock#2){+.+.}-{3:3}, at: l2cap_chan_connect+0x7fd/0xe30 net/bluetooth/l2cap_core.c:7318
1 lock held by syz.1.39/6005:
 #0: ffff8880756140b8 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
1 lock held by syz.2.19/6009:
 #0: ffff8880756140b8 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
1 lock held by syz.0.17/6010:
 #0: ffff8880756140b8 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
1 lock held by syz.4.40/6091:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.7.43/6092:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.5.41/6093:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.6.42/6094:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.8.44/6146:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.9.45/6172:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.1.46/6173:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.3.47/6174:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.0.48/6191:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.2.49/6253:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.4.50/6254:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.6.51/6259:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.7.52/6271:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.5.53/6348:
 #0: ffffffff8e56da30 (
hidp_session_sem
){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.8.54/6351:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.9.55/6356:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
1 lock held by syz.1.56/6358:
 #0: ffffffff8e56da30 (hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
3 locks held by modprobe/6366:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf59/0xfa0 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 33 Comm: kworker/u4:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55
Code: 65 8b 05 5d f7 70 75 65 8b 0d 52 f7 70 75 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04
RSP: 0018:ffffc90000a9f7c8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff888018e90000 RCX: ae03fba973fda400
RDX: dffffc0000000000 RSI: ffffffff8acad9c0 RDI: ffffffff8b1d4020
RBP: ffffc90000a9f8a8 R08: ffffffff8e8c626f R09: 1ffffffff1d18c4d
R10: dffffc0000000000 R11: fffffbfff1d18c4e R12: dffffc0000000000
R13: ffff8880b8f39050 R14: 4b0e257b5fd8d71b R15: 0000000000000200
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f10352b79b0 CR3: 000000000cf32000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 lockdep_recursion_inc kernel/locking/lockdep.c:462 [inline]
 lockdep_hardirqs_on_prepare+0x1b6/0x7d0 kernel/locking/lockdep.c:4386
 trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:61
 crng_make_state+0x350/0x700 drivers/char/random.c:365
 _get_random_bytes+0x100/0x250 drivers/char/random.c:378
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:775 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
 nsim_dev_trap_report_work+0x5fe/0xa90 drivers/net/netdevsim/dev.c:851
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>