INFO: task kworker/u8:8:3496 blocked for more than 143 seconds. Not tainted 6.13.0-syzkaller-01005-gb9d8a295ed6b #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:8 state:D stack:22672 pid:3496 tgid:3496 ppid:2 flags:0x00004000 Workqueue: events_unbound flush_to_ldisc Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0xe58/0x5ad0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 __mutex_lock_common kernel/locking/mutex.c:665 [inline] __mutex_lock+0x62b/0xa60 kernel/locking/mutex.c:735 commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:756 n_tty_receive_char+0x3d8/0x600 drivers/tty/n_tty.c:1437 n_tty_receive_buf_standard+0x6aa/0x3180 drivers/tty/n_tty.c:1606 __receive_buf drivers/tty/n_tty.c:1640 [inline] n_tty_receive_buf_common+0x8ed/0x1980 drivers/tty/n_tty.c:1739 tty_ldisc_receive_buf+0xa2/0x190 drivers/tty/tty_buffer.c:387 tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37 receive_buf drivers/tty/tty_buffer.c:445 [inline] flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Showing all locks held in the system: 2 locks held by kworker/u8:0/11: 3 locks held by kworker/u8:1/12: 5 locks held by kworker/1:0/25: 1 lock held by khungtaskd/30: #0: ffffffff8e1bbc80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e1bbc80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e1bbc80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6744 3 locks held by kworker/u8:2/33: 3 locks held by kworker/u8:4/68: #0: ffff88801b081148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc9000213fd80 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 #2: ffffffff8fef1f88 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:285 5 locks held by kworker/u8:5/1081: 3 locks held by kworker/u8:7/1162: #0: ffff88814d1a1948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc9000450fd80 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 #2: ffffffff8fef1f88 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4755 6 locks held by kworker/u8:8/3496: #0: ffff88801b081148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211 #1: ffffc9000d667d80 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212 #2: ffff8880622230b8 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x31/0x780 drivers/tty/tty_buffer.c:467 #3: ffff888061c000a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263 #4: ffff888061c002e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_receive_buf_common+0x85/0x1980 drivers/tty/n_tty.c:1702 #5: ffffc900041b5380 (&ldata->output_lock){+.+.}-{4:4}, at: commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:756 2 locks held by syslogd/5173: 4 locks held by udevd/5191: 5 locks held by dhcpcd/5485: 2 locks held by getty/5569: #0: ffff8881491350a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 2 locks held by syz-executor/5803: 1 lock held by syz-executor/5814: 1 lock held by syz-executor/5818: 6 locks held by syz.1.4924/16107: 3 locks held by kworker/u8:9/16108: 2 locks held by syz-executor/16109: 1 lock held by syz-executor/16110: 3 locks held by kworker/u8:11/16114: 3 locks held by kworker/0:3/16116: 2 locks held by syz-executor/16117: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-syzkaller-01005-gb9d8a295ed6b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline] watchdog+0xf14/0x1240 kernel/hung_task.c:397 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 25 Comm: kworker/1:0 Not tainted 6.13.0-syzkaller-01005-gb9d8a295ed6b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: wg-crypt-wg0 wg_packet_tx_worker RIP: 0010:get_current arch/x86/include/asm/current.h:49 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x70 kernel/kcov.c:216 Code: ff ff ff 31 c0 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <65> 48 8b 15 84 ae 69 7e 65 8b 05 85 ae 69 7e a9 00 01 ff 00 48 8b RSP: 0018:ffffc90000a17d48 EFLAGS: 00000282 RAX: fffff52000142fb3 RBX: dffffc0000000000 RCX: ffffffff8a0cbcc3 RDX: ffff88804ada7640 RSI: 0000000000000000 RDI: ffff88802eaf1e40 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000005 R12: 0000000000000001 R13: ffff88804ada76bf R14: 000000000000000a R15: ffff88804ada7640 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f90a8845630 CR3: 0000000034bc4000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_ext_exist include/linux/skbuff.h:4876 [inline] skb_ext_find include/linux/skbuff.h:4887 [inline] nf_bridge_info_get include/linux/netfilter_bridge.h:30 [inline] br_nf_dev_queue_xmit+0x6d/0x2a20 net/bridge/br_netfilter_hooks.c:863 NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] br_nf_post_routing+0x8ee/0x11b0 net/bridge/br_netfilter_hooks.c:997 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook+0x474/0x7d0 include/linux/netfilter.h:269 NF_HOOK include/linux/netfilter.h:312 [inline] br_forward_finish+0xcd/0x130 net/bridge/br_forward.c:66 br_nf_hook_thresh+0x303/0x410 net/bridge/br_netfilter_hooks.c:1198 br_nf_forward_finish+0x66a/0xba0 net/bridge/br_netfilter_hooks.c:693 NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] br_nf_forward_ip.part.0+0x610/0x820 net/bridge/br_netfilter_hooks.c:747 br_nf_forward_ip net/bridge/br_netfilter_hooks.c:707 [inline] br_nf_forward+0xf11/0x1bd0 net/bridge/br_netfilter_hooks.c:804 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook+0x474/0x7d0 include/linux/netfilter.h:269 NF_HOOK include/linux/netfilter.h:312 [inline] __br_forward+0x1be/0x5b0 net/bridge/br_forward.c:115 deliver_clone+0x5b/0xa0 net/bridge/br_forward.c:131 br_flood+0x493/0x5c0 net/bridge/br_forward.c:245 br_handle_frame_finish+0xda5/0x1c80 net/bridge/br_input.c:215 br_nf_hook_thresh+0x303/0x410 net/bridge/br_netfilter_hooks.c:1198 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154 NF_HOOK include/linux/netfilter.h:314 [inline] br_nf_pre_routing_ipv6+0x3ce/0x8c0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:536 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_bridge_pre net/bridge/br_input.c:277 [inline] br_handle_frame+0x9eb/0x1490 net/bridge/br_input.c:424 __netif_receive_skb_core.constprop.0+0xa76/0x4470 net/core/dev.c:5598 __netif_receive_skb_one_core+0xb1/0x1e0 net/core/dev.c:5702 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5817 process_backlog+0x443/0x15f0 net/core/dev.c:6149 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6902 napi_poll net/core/dev.c:6971 [inline] net_rx_action+0xa94/0x1010 net/core/dev.c:7093 handle_softirqs+0x213/0x8f0 kernel/softirq.c:561 do_softirq kernel/softirq.c:462 [inline] do_softirq+0xb2/0xf0 kernel/softirq.c:449 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:389 wg_socket_send_skb_to_peer+0x14c/0x220 drivers/net/wireguard/socket.c:184 wg_packet_create_data_done drivers/net/wireguard/send.c:251 [inline] wg_packet_tx_worker+0x1aa/0x810 drivers/net/wireguard/send.c:276 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244