INFO: task khidpd_0b574155:15010 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:khidpd_0b574155 state:D stack:28616 pid:15010 ppid:2 flags:0x00004000
Call Trace:
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
Showing all locks held in the system:
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
2 locks held by getty/5532:
#0: ffff8880317620a0 (&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
3 locks held by kworker/1:3/5775:
#0: ffff888017c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#0: ffff888017c70d38 ((wq_completion)events#2){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#1: ffffc900045b7d00 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#1: ffffc900045b7d00 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#2: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
#2: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004
3 locks held by kworker/1:6/5854:
2 locks held by kworker/1:7/5863:
#0: ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#0: ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#1: ffffc900049f7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#1: ffffc900049f7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
2 locks held by kworker/u4:11/12640:
3 locks held by kworker/0:0/14134:
1 lock held by syz-executor/14591:
2 locks held by khidpd_0b574155/15010:
#0: ffff888026b5e338 (&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.4.2687/15567:
#0: ffff88805d4780b8 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
#1: ffff888026b5e338 (&conn->lock#2){+.+.}-{3:3}, at: l2cap_chan_connect+0x7fd/0xe30 net/bluetooth/l2cap_core.c:7318
1 lock held by syz.5.2780/16017:
#0:
ffffffff8e56da30
(hidp_session_sem){++++}-{3:3}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1046
2 locks held by syz-executor/16146:
5 locks held by syz.1.2894/16404:
#0: ffff8880622ece70 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:521 [inline]
#0: ffff8880622ece70 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x212/0x500 net/bluetooth/hci_core.c:2709
#1: ffff8880622ec0b8 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x552/0x1170 net/bluetooth/hci_sync.c:5396
#2: ffffffff8e541a68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2016 [inline]
#2: ffffffff8e541a68 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0x99/0x220 net/bluetooth/hci_conn.c:2592
#3:
ffff8880242a4338 (&conn->lock#2){+.+.}-{3:3}, at: l2cap_conn_del+0x7b/0x630 net/bluetooth/l2cap_core.c:1796
#4: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
#4: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004
=============================================
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:
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
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12639 Comm: kworker/u4:10 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:lockdep_hardirqs_on_prepare+0x172/0x7d0 kernel/locking/lockdep.c:4384
Code: 27 9a 7e 85 c0 0f 85 37 04 00 00 48 89 5c 24 18 65 48 8b 1d 00 58 9b 7e 48 8d bb d8 0a 00 00 48 89 f8 48 c1 e8 03 80 3c 10 00 <74> 0f e8 47 d8 77 00 48 ba 00 00 00 00 00 fc ff df 4c 8b b3 d8 0a
RSP: 0018:ffffc900031a7920 EFLAGS: 00000046
RAX: 1ffff110048dd15b RBX: ffff8880246e8000 RCX: ffffffff972f7403
RDX: dffffc0000000000 RSI: ffffffff8b1d4000 RDI: ffff8880246e8ad8
RBP: ffffc900031a79c8 R08: ffffffff8e8c626f R09: 1ffffffff1d18c4d
R10: dffffc0000000000 R11: fffffbfff1d18c4e R12: dffffc0000000000
R13: 0000000000000a06 R14: ffffffff8d22ec40 R15: 1ffff92000634f3c
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e7bfd2b558 CR3: 000000000cf32000 CR4: 00000000003506e0
Call Trace:
trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:61
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
_raw_spin_unlock_irqrestore+0x86/0x120 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
prepare_to_wait_event+0x434/0x470 kernel/sched/wait.c:340
toggle_allocation_gate+0x137/0x260 mm/kfence/core.c:849
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