INFO: task rcu_tasks_kthre:12 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:rcu_tasks_kthre state:D stack:28256 pid:12 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5246 [inline]
__schedule+0x107f/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x2c2/0x590 kernel/sched/completion.c:138
__synchronize_srcu+0x2b3/0x350 kernel/rcu/srcutree.c:1243
rcu_tasks_wait_gp+0x49f/0xac0 kernel/rcu/tasks.h:693
rcu_tasks_one_gp+0xd27/0xef0 kernel/rcu/tasks.h:534
rcu_tasks_kthread+0x6e/0x90 kernel/rcu/tasks.h:562
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cb2e4f0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cb2ed10 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
3 locks held by kworker/1:0/22:
1 lock held by khungtaskd/28:
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2db60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
2 locks held by getty/4029:
#0: ffff88803058f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
2 locks held by syz-executor/11361:
2 locks held by kworker/0:0/13551:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc90003387d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/0:6/14412:
#0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc900039efd00 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
3 locks held by syz-executor/14844:
#0: ffff8880325b54b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:526 [inline]
#0: ffff8880325b54b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x20e/0x500 net/bluetooth/hci_core.c:2733
#1: ffff8880325b4428 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x506/0x1120 net/bluetooth/hci_sync.c:5271
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1834 [inline]
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2532
3 locks held by kworker/u4:6/16542:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000c58fd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb33700 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x5e0 kernel/rcu/tree.c:4023
3 locks held by kworker/u4:33/16563:
#0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#1: ffffc9000c6dfd00 ((work_completion)(&map->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
#2: ffffffff8cb33838 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.1.4117/17978:
#0: ffffffff8cb82e28 (event_mutex){+.+.}-{3:3}, at: perf_trace_destroy+0x2a/0x140 kernel/trace/trace_event_perf.c:239
3 locks held by syz.2.4115/17986:
#0: ffff888078de94b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:526 [inline]
#0: ffff888078de94b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_unregister_dev+0x20e/0x500 net/bluetooth/hci_core.c:2733
#1: ffff888078de8428 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_close_sync+0x506/0x1120 net/bluetooth/hci_sync.c:5271
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1834 [inline]
#2: ffffffff8deb9d28 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xac/0x290 net/bluetooth/hci_conn.c:2532
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 28 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+0x188/0x24e lib/dump_stack.c:106
nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf0e/0xf50 kernel/hung_task.c:377
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 16 Comm: rcu_preempt Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__this_cpu_preempt_check+0x3/0x10 lib/smp_processor_id.c:66
Code: e8 12 b8 f4 ff 48 8b 74 24 30 48 c7 c7 60 5e df 8a e8 01 b8 f4 ff e8 0a 8c ff ff eb a8 e8 35 ea ff ff 0f 1f 44 00 00 48 89 fe <48> c7 c7 e0 5d df 8a e9 e1 fe ff ff 00 eb 1e 0f 1f 00 48 89 f8 48
RSP: 0018:ffffc90000157918 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 1ffff11027fdcca0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8a8c2920 RDI: ffffffff8a8c2920
RBP: ffffc900001579f0 R08: ffff88807f227dab R09: 1ffff1100fe44fb5
R10: dffffc0000000000 R11: ffffed100fe44fb6 R12: ffff88813fee64e0
R13: 0000000000000046 R14: ffff88813fee6504 R15: 1ffff9200002af28
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a13d070000 CR3: 000000007f883000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
lock_unpin_lock+0x273/0x470 kernel/locking/lockdep.c:5777
rq_unpin_lock kernel/sched/sched.h:1593 [inline]
prepare_lock_switch kernel/sched/core.c:4988 [inline]
context_switch kernel/sched/core.c:5243 [inline]
__schedule+0x1006/0x4030 kernel/sched/core.c:6563
schedule+0xb9/0x180 kernel/sched/core.c:6639
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295