INFO: task kworker/u8:14:7370 blocked for more than 153 seconds.
Not tainted 6.16.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:14 state:D stack:21160 pid:7370 tgid:7370 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
__schedule_loop kernel/sched/core.c:6864 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6879
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6936
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x724/0xe80 kernel/locking/mutex.c:747
commit_echoes drivers/tty/n_tty.c:740 [inline]
n_tty_receive_char+0x683/0xc30 drivers/tty/n_tty.c:1421
n_tty_receive_buf_standard+0x5e2/0x5150 drivers/tty/n_tty.c:1590
__receive_buf drivers/tty/n_tty.c:1624 [inline]
n_tty_receive_buf_common+0xab3/0x12f0 drivers/tty/n_tty.c:1723
tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x24a/0x720 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
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>
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e13f0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
4 locks held by kworker/u8:4/61:
2 locks held by kworker/0:2/1207:
3 locks held by kworker/u8:5/1316:
3 locks held by kworker/u8:6/1335:
5 locks held by kworker/1:2/2153:
2 locks held by kworker/R-bat_e/3414:
6 locks held by kworker/u8:8/3504:
1 lock held by klogd/5196:
3 locks held by udevd/5207:
1 lock held by dhcpcd/5501:
1 lock held by dhcpcd/5502:
1 lock held by crond/5579:
2 locks held by getty/5594:
#0: ffff888030c590a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036be2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/5824:
1 lock held by syz-executor/5834:
3 locks held by syz-executor/5850:
6 locks held by kworker/u8:14/7370:
#0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
#0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
#1: ffffc9000b187bc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
#1: ffffc9000b187bc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
#2: ffff888026dce0b8 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x38/0x720 drivers/tty/tty_buffer.c:467
#3: ffff888059e8b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
#4: ffff888059e8b2e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_receive_buf_common+0x84/0x12f0 drivers/tty/n_tty.c:1686
#5: ffffc9000ad8b380 (&ldata->output_lock){+.+.}-{4:4}, at: commit_echoes drivers/tty/n_tty.c:740 [inline]
#5: ffffc9000ad8b380 (&ldata->output_lock){+.+.}-{4:4}, at: n_tty_receive_char+0x683/0xc30 drivers/tty/n_tty.c:1421
4 locks held by kworker/1:7/8388:
3 locks held by kworker/u8:17/8838:
3 locks held by kworker/u8:23/8846:
4 locks held by kworker/u8:25/8848:
3 locks held by kworker/u8:29/8853:
4 locks held by kworker/u8:33/8857:
4 locks held by kworker/u8:34/8858:
4 locks held by kworker/u8:35/8860:
4 locks held by kworker/u8:37/8862:
2 locks held by kworker/u8:38/8863:
#0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
#0: ffff88801a489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
#1: ffffc90002e07bc0 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
#1: ffffc90002e07bc0 ((work_completion)(&pool->idle_cull_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
4 locks held by kworker/u8:39/8864:
2 locks held by kworker/u8:40/8865:
4 locks held by kworker/u8:41/8866:
6 locks held by kworker/u8:42/8867:
4 locks held by kworker/u8:43/8868:
4 locks held by kworker/u8:44/8869:
1 lock held by kworker/u8:46/8872:
2 locks held by syz.5.1241/10669:
2 locks held by syz.4.1243/10681:
6 locks held by syz.4.1243/10685:
1 lock held by dhcpcd/10683:
1 lock held by syz-executor/10686:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8867 Comm: kworker/u8:42 Not tainted 6.16.0-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: wg-kex-wg2 wg_packet_handshake_send_worker
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp2+0x11/0x90 kernel/kcov.c:307
Code: 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 14 25 08 90 9c 92 <65> 8b 0d b8 66 dc 10 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75
RSP: 0018:ffffc90000007238 EFLAGS: 00000246
RAX: ffffffff8a3f1555 RBX: 0000000000000000 RCX: ffff88807fddda00
RDX: ffff88807fddda00 RSI: 0000000000000000 RDI: 000000000000ffff
RBP: ffffc900000073f0 R08: ffffffff8fa0b3f7 R09: 1ffffffff1f4167e
R10: dffffc0000000000 R11: fffffbfff1f4167f R12: 1ffff92000000e58
R13: dffffc0000000000 R14: ffff88805a12b0c6 R15: 1ffff1100988746a
FS: 0000000000000000(0000) GS:ffff888125c57000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055bb60c61660 CR3: 00000000349fe000 CR4: 00000000003526f0
Call Trace:
<IRQ>
is_broadcast_ether_addr include/linux/etherdevice.h:179 [inline]
br_handle_frame_finish+0x755/0x19b0 net/bridge/br_input.c:151
br_nf_hook_thresh+0x3c6/0x4a0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0x948/0xd00 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:317 [inline]
br_nf_pre_routing_ipv6+0x37e/0x6b0 net/bridge/br_netfilter_ipv6.c:184
nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
br_handle_frame+0x97f/0x14c0 net/bridge/br_input.c:434
__netif_receive_skb_core+0x10e1/0x4180 net/core/dev.c:5863
__netif_receive_skb_one_core net/core/dev.c:5975 [inline]
__netif_receive_skb+0x72/0x380 net/core/dev.c:6090
process_backlog+0x60e/0x14f0 net/core/dev.c:6442
__napi_poll+0xc4/0x480 net/core/dev.c:7414
napi_poll net/core/dev.c:7478 [inline]
net_rx_action+0x707/0xe30 net/core/dev.c:7605
handle_softirqs+0x283/0x870 kernel/softirq.c:579
do_softirq+0xec/0x180 kernel/softirq.c:480
</IRQ>
<TASK>
__local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:407
spin_unlock_bh include/linux/spinlock.h:396 [inline]
wg_index_hashtable_insert+0xff/0x880 drivers/net/wireguard/peerlookup.c:126
wg_noise_handshake_create_initiation+0x5e1/0x7e0 drivers/net/wireguard/noise.c:569
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:34 [inline]
wg_packet_handshake_send_worker+0x163/0x320 drivers/net/wireguard/send.c:51
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
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>