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: 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 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: 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 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: 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 __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