INFO: task khidpd_0b574155:6569 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:6569 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
INFO: task syz.2.225:6599 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.225 state:D stack:26952 pid:6599 ppid:5778 flags:0x00004004
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_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: 0033:0x7f802479e199
RSP: 002b:00007f80256b5028 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f8024a25fa0 RCX: 00007f802479e199
RDX: 000000000000000e RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f80248358e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8024a26038 R14: 00007f8024a25fa0 R15: 00007ffce2e0bb38
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
3 locks held by kworker/0:2/55:
#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: ffffc9000130fd00 (key_gc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#1: ffffc9000130fd00 (key_gc_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:324 [inline]
, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004
3 locks held by kworker/u4:13/2961:
#0: ffff88801a25d138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#0: ffff88801a25d138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#1: ffffc9000bc3fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#1: ffffc9000bc3fd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#2: ffffffff8e3c5d90 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x140/0xb00 net/core/net_namespace.c:610
2 locks held by getty/5533:
#0: ffff88802d1cf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032832f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x428/0x1370 drivers/tty/n_tty.c:2217
2 locks held by kworker/0:3/5817:
#0:
ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
ffff888017c72d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
#1: ffffc90004877d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2632 [inline]
#1: ffffc90004877d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x975/0x1600 kernel/workqueue.c:2734
3 locks held by kworker/0:4/5818:
2 locks held by khidpd_0b574155/6569:
#0: ffff88807f540b38 (&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.2.225/6599:
#0: ffff88807b2100b8 (&hdev->lock){+.+.}-{3:3}, at: l2cap_chan_connect+0xfc/0xe30 net/bluetooth/l2cap_core.c:7195
#1: ffff88807f540b38 (&conn->lock#2){+.+.}-{3:3}, at: l2cap_chan_connect+0x7fd/0xe30 net/bluetooth/l2cap_core.c:7318
1 lock held by syz-executor/7364:
#0: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
#0: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3da/0x880 kernel/rcu/tree_exp.h:1004
1 lock held by cmp/7960:
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7960 Comm: cmp Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:vsnprintf+0x56/0x1ba0 lib/vsprintf.c:-1
Code: 24 48 e8 7d 70 04 f7 48 c7 44 24 40 00 00 00 00 bf ff ff ff 7f 48 89 de e8 a7 74 04 f7 48 f7 c3 00 00 00 80 0f 85 df 1a 00 00 <48> b9 00 00 00 00 00 fc ff df 49 8d 04 1e 4c 39 f0 4c 89 f5 48 f7
RSP: 0018:ffffc9000b9ffa38 EFLAGS: 00000246
RAX: ffffffff8a832049 RBX: 0000000000000cec RCX: ffff888024915a00
RDX: 0000000000000000 RSI: 0000000000000cec RDI: 000000007fffffff
RBP: ffffc9000b9ffbd0 R08: ffffc9000b9ffb57 R09: 0000000000000000
R10: ffffc9000b9ffb40 R11: fffff5200173ff6b R12: ffff88805edfca68
R13: ffff88807f56e314 R14: ffff88807f56e314 R15: ffffffff8ad800c0
FS: 00007fe70acaec80(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe70af4a7b0 CR3: 000000001de6d000 CR4: 00000000003506f0
Call Trace:
seq_vprintf fs/seq_file.c:391 [inline]
seq_printf+0x189/0x290 fs/seq_file.c:406
filesystems_proc_show+0x9a/0x100 fs/filesystems.c:248
seq_read_iter+0x464/0xc50 fs/seq_file.c:230
proc_reg_read_iter+0x1af/0x280 fs/proc/inode.c:305
call_read_iter include/linux/fs.h:2012 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x486/0x990 fs/read_write.c:470
ksys_read+0x151/0x260 fs/read_write.c:613
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: 0033:0x7fe70adfe407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fffda35bdf0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fe70acaec80 RCX: 00007fe70adfe407
RDX: 0000000000000400 RSI: 0000560d548c2500 RDI: 0000000000000003
RBP: 00007fe70af46ff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fffda35bed8
R13: 00007fe70af46ea0 R14: 00007fe70ad4a4d0 R15: 0000000000000000