INFO: task syz-executor:5844 blocked for more than 140 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22328 pid:5844 tgid:5844 ppid:1 task_flags:0x40054c flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x81b/0x1060 kernel/locking/mutex.c:760 tun_detach drivers/net/tun.c:634 [inline] tun_chr_close+0x38/0x230 drivers/net/tun.c:3433 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x14d/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x86f/0x2bf0 kernel/exit.c:961 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f94d578d5fc RSP: 002b:00007ffc2ad12570 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffe00 RBX: 00000000ffffffff RCX: 00007f94d578d5fc RDX: 0000000000000030 RSI: 00007ffc2ad12630 RDI: 00000000000000f9 RBP: 00007ffc2ad125dc R08: 0000000000000000 R09: 00007ffc2ad122e7 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000000d5 R13: 0000000000000000 R14: 0000000000062f52 R15: 00007ffc2ad12630 Showing all locks held in the system: 2 locks held by kworker/0:0/9: 4 locks held by kworker/u8:1/13: #0: ffff88801c6f4148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90000127d10 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff9036d010 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x890 net/core/net_namespace.c:658 #3: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1b/0x230 drivers/net/wireguard/device.c:417 1 lock held by khungtaskd/31: #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c1220 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 2 locks held by kworker/1:1/43: 5 locks held by kworker/u9:0/51: #0: ffff88802aff3148 ((wq_completion)hci0){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90000bb7d10 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff8880336d4dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x430 net/bluetooth/hci_sync.c:331 #3: ffff8880336d40b8 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x13f/0xb20 net/bluetooth/hci_sync.c:5670 #4: ffffffff905eb368 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:2079 [inline] #4: ffffffff905eb368 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_failed+0x14f/0x330 net/bluetooth/hci_conn.c:1289 3 locks held by kworker/u8:4/59: #0: ffff888031853948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000210fd10 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4734 3 locks held by kworker/u8:5/3551: #0: ffff88801b881148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc9000c5b7d10 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:303 2 locks held by getty/5603: #0: ffff88803621e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 1 lock held by syz-executor/5843: 1 lock held by syz-executor/5844: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3433 3 locks held by kworker/u9:2/5848: #0: ffff888024f24148 ((wq_completion)hci1){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900031b7d10 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888034434dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x430 net/bluetooth/hci_sync.c:331 4 locks held by kworker/u9:3/5850: #0: ffff88807950c148 ((wq_completion)hci7){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc900031a7d10 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff888079204dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x430 net/bluetooth/hci_sync.c:331 #3: ffff8880792040b8 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x13f/0xb20 net/bluetooth/hci_sync.c:5670 2 locks held by kworker/0:3/5857: 6 locks held by kworker/u9:6/5860: #0: ffff8880253bf148 ((wq_completion)hci4#2){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90003137d10 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffff8880340d8dc0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x175/0x430 net/bluetooth/hci_sync.c:331 #3: ffff8880340d80b8 (&hdev->lock){+.+.}-{4:4}, at: hci_abort_conn_sync+0x13f/0xb20 net/bluetooth/hci_sync.c:5670 #4: ffffffff905eb368 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:2079 [inline] #4: ffffffff905eb368 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_failed+0x14f/0x330 net/bluetooth/hci_conn.c:1289 #5: ffff8881467b4b38 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x730 net/bluetooth/l2cap_core.c:1762 2 locks held by kworker/1:3/5955: 3 locks held by kworker/1:6/5993: #0: ffff88801b878d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3211 #1: ffffc90002f97d10 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3212 #2: ffffffff8e5cc7b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343 1 lock held by syz-executor/9764: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3433 7 locks held by kworker/1:7/9770: 2 locks held by syz-executor/9781: #0: ffffffff9036d010 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:566 #1: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: wg_netns_pre_exit+0x1b/0x230 drivers/net/wireguard/device.c:417 1 lock held by syz-executor/9799: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9803: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9807: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9811: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9817: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9828: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9831: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 3 locks held by kworker/1:8/9833: 1 lock held by syz-executor/9835: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9841: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 1 lock held by syz-executor/9846: #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff90383308 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x30c/0x1540 net/ipv4/devinet.c:979 2 locks held by dhcpcd/9849: 1 lock held by dhcpcd/9850: #0: ffff8880308d0258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff8880308d0258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3251 1 lock held by dhcpcd/9851: #0: ffff88802bc0e258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff88802bc0e258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3251 1 lock held by dhcpcd/9852: #0: ffff88802bc0c258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff88802bc0c258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3251 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9770 Comm: kworker/1:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: wg-crypt-wg1 wg_packet_tx_worker RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:240 Code: 48 8b 05 bb ea 1a 12 48 8b 80 30 16 00 00 c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 87 ea 1a 12 65 8b 05 98 ea RSP: 0018:ffffc9000472f068 EFLAGS: 00000086 RAX: 0000000000000000 RBX: ffff8880b8536514 RCX: ffffffff84e478d2 RDX: 0000000000000005 RSI: 0000000000000010 RDI: 0000000000000005 RBP: ffffc9000472f0b4 R08: 0000000000000001 R09: 0000000000000010 R10: 0000000000000004 R11: 0000000094062014 R12: ffffc9000472f18c R13: 0000000000000005 R14: ffffc9000472f178 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881247b9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4ebe0b3de2 CR3: 000000000e380000 CR4: 00000000003526f0 Call Trace: chacha_block_generic+0x202/0x330 lib/crypto/chacha.c:85 chacha20_block include/crypto/chacha.h:45 [inline] _get_random_bytes+0x16b/0x1e0 drivers/char/random.c:418 get_random_u16+0x261/0x7e0 drivers/char/random.c:553 cake_get_flow_quantum+0xd9/0x290 net/sched/sch_cake.c:687 cake_dequeue+0x1be7/0x4830 net/sched/sch_cake.c:2119 dequeue_skb net/sched/sch_generic.c:294 [inline] qdisc_restart net/sched/sch_generic.c:399 [inline] __qdisc_run+0x1bd/0x1bf0 net/sched/sch_generic.c:417 __dev_xmit_skb net/core/dev.c:4183 [inline] __dev_queue_xmit+0x2b43/0x4490 net/core/dev.c:4691 dev_queue_xmit include/linux/netdevice.h:3361 [inline] neigh_hh_output include/net/neighbour.h:531 [inline] neigh_output include/net/neighbour.h:545 [inline] ip6_finish_output2+0xe98/0x2020 net/ipv6/ip6_output.c:141 __ip6_finish_output+0x3cd/0x1010 net/ipv6/ip6_output.c:215 ip6_finish_output net/ipv6/ip6_output.c:226 [inline] NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip6_output+0x1ca/0x3e0 net/ipv6/ip6_output.c:248 dst_output include/net/dst.h:461 [inline] ip6_local_out+0xd1/0x4d0 net/ipv6/output_core.c:155 ip6tunnel_xmit include/net/ip6_tunnel.h:162 [inline] udp_tunnel6_xmit_skb+0x7f1/0xc50 net/ipv6/ip6_udp_tunnel.c:112 send6+0x4ba/0xd30 drivers/net/wireguard/socket.c:152 wg_socket_send_skb_to_peer+0xf6/0x210 drivers/net/wireguard/socket.c:178 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+0x9cf/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245