Kernel bug: INFO: task hung in hidp_session_remove
Subsystem: kernel
Status: open

Crash report:
INFO: task khidpd_000d2f19:5507 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc3-syzkaller-00306-gaaf724ed6926 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:khidpd_000d2f19 state:D stack:29000 pid:5507  tgid:5507  ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
 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+0x2bf/0x5d0 kernel/sched/completion.c:148
 __flush_work+0x9b9/0xbc0 kernel/workqueue.c:4246
 __cancel_work_sync+0xbe/0x110 kernel/workqueue.c:4366
 hidp_session_remove+0x62/0x260 net/bluetooth/hidp/core.c:1169
 l2cap_unregister_user+0x18e/0x1b0 net/bluetooth/l2cap_core.c:1734
 hidp_session_thread+0x3c9/0x410 net/bluetooth/hidp/core.c:1304
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz.0.54:5547 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc3-syzkaller-00306-gaaf724ed6926 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.54        state:D stack:28008 pid:5547  tgid:5547  ppid:5445   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
 l2cap_chan_connect+0x102/0xe30 net/bluetooth/l2cap_core.c:6964
 l2cap_sock_connect+0x5c5/0x7a0 net/bluetooth/l2cap_sock.c:256
 __sys_connect_file net/socket.c:2038 [inline]
 __sys_connect+0x316/0x440 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f23aef8e929
RSP: 002b:00007ffe899a2238 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f23af1b5fa0 RCX: 00007f23aef8e929
RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f23af010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f23af1b5fa0 R14: 00007f23af1b5fa0 R15: 0000000000000003
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/26:
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
4 locks held by kworker/u4:4/1034:
 #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88801a479148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
 #1: ffffc900024c7bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc900024c7bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
 #2: ffffffff8f50f788 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
 #3: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
 #3: ffffffff8e144978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:998
3 locks held by kworker/0:3/1353:
2 locks held by getty/5111:
 #0: ffff8880002c90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000018e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by khidpd_000d2f19/5507:
 #0: ffff88804f23c0b8 (&hdev->lock){+.+.}-{4:4}, at: l2cap_unregister_user+0x6a/0x1b0 net/bluetooth/l2cap_core.c:1728
 #1: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_remove+0x2c/0x260 net/bluetooth/hidp/core.c:1165
1 lock held by syz.0.54/5547:
 #0: ffff88804f23c0b8 (&hdev->lock){+.+.}-{4:4}, at: l2cap_chan_connect+0x102/0xe30 net/bluetooth/l2cap_core.c:6964
1 lock held by syz.1.55/5578:
 #0: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1026
1 lock held by syz.2.56/5616:
 #0: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1026
1 lock held by syz.3.57/5652:
 #0: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1026
1 lock held by syz.4.58/5688:
 #0: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1026
1 lock held by syz.5.59/5724:
 #0: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1026
1 lock held by syz.6.60/5768:
 #0: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1026
1 lock held by syz.7.61/5804:
 #0: ffffffff8f6a0890 (hidp_session_sem){++++}-{4:4}, at: hidp_session_find+0x1a/0x100 net/bluetooth/hidp/core.c:1026
1 lock held by syz-executor/5806:
 #0: ffffffff8f50f788 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8f50f788 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff8f50f788 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4054

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 26 Comm: khungtaskd Not tainted 6.16.0-rc3-syzkaller-00306-gaaf724ed6926 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>