INFO: task khidpd_04f34155:17716 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:khidpd_04f34155 state:D stack:28616 pid:17716 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>

Showing all locks held in the system:
1 lock held by khungtaskd/28:
 #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/5529:
 #0: ffff88802d00c0a0 (&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/0:5/6718:
2 locks held by khidpd_04f34155/17716:
 #0: ffff88807d760338 (&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.5.3246/18230:
 #0: ffff888017bb80b8 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
 #1: ffff88807d760338 (&conn->lock#2){+.+.}-{3:3}, at: l2cap_chan_connect+0x7fd/0xe30 net/bluetooth/l2cap_core.c:7318

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 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>