INFO: task getty:3949 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:getty state:D stack:22288 pid: 3949 ppid: 1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11c3/0x4350 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093 do_wait_for_common+0x295/0x460 kernel/sched/completion.c:85 __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x48/0x60 kernel/sched/completion.c:138 __flush_work+0x15a/0x210 kernel/workqueue.c:3094 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181 hci_unregister_dev+0x163/0x590 net/bluetooth/hci_core.c:4061 hci_uart_tty_close+0x268/0x330 drivers/bluetooth/hci_ldisc.c:575 tty_ldisc_reinit+0xe4/0x460 drivers/tty/tty_ldisc.c:679 tty_ldisc_hangup+0x360/0x4a0 drivers/tty/tty_ldisc.c:745 __tty_hangup+0x44e/0x670 drivers/tty/tty_io.c:639 disassociate_ctty+0x38d/0x860 drivers/tty/tty_jobctrl.c:275 do_exit+0x5f9/0x2110 kernel/exit.c:888 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 __do_sys_exit_group kernel/exit.c:1015 [inline] __se_sys_exit_group kernel/exit.c:1013 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fb402a646c5 RSP: 002b:00007ffec7588838 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fb402b65fe8 RCX: 00007fb402a646c5 RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000001 RBP: 0000000000000001 R08: 00007ffec75887c8 R09: 0000000000000000 R10: 00007ffec7588660 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fb402b64680 R15: 00007fb402b66000 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8c31ef60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 4 locks held by kworker/u4:3/155: 1 lock held by dhcpcd/3852: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x256/0x1ba0 net/ipv4/devinet.c:1076 2 locks held by getty/3949: #0: ffff88802c0961c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: __tty_hangup+0xc0/0x670 drivers/tty/tty_io.c:599 #1: ffff88802c096098 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:300 [inline] ffff88802c096098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x68/0xb0 drivers/tty/tty_ldisc.c:324 3 locks held by kworker/u5:8/4204: #0: ffff88802b2d2938 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000304fd00 ((work_completion)(&hdev->power_on)){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffff88805efb93f0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_open+0xa4/0x12a0 net/bluetooth/hci_core.c:1464 3 locks held by kworker/u4:8/4413: #0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc90003467d00 ( (linkwatch_work).work ){+.+.}-{0:0} , at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251 3 locks held by kworker/0:20/5836: #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1 #1: ffffc9000330fd00 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285 #2: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 3 locks held by kworker/u4:12/5972: 1 lock held by syz.3.824/7730: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x256/0x1ba0 net/ipv4/devinet.c:1076 1 lock held by syz.3.824/7736: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695 1 lock held by syz.3.824/7738: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695 1 lock held by syz.5.826/7742: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline] #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x79f/0xf10 net/core/rtnetlink.c:5695 1 lock held by syz.8.829/7751: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1f30 drivers/net/tun.c:3066 1 lock held by syz.8.829/7754: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: __tun_chr_ioctl+0x3f3/0x1f30 drivers/net/tun.c:3066 1 lock held by syz.8.829/7756: #0: ffffffff8d44d548 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x256/0x1ba0 net/ipv4/devinet.c:1076 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 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+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xe1b/0xe60 kernel/hung_task.c:369 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 1 to CPUs 0: net_ratelimit: 75 callbacks suppressed wireguard: wg0: Sending keepalive packet to peer 55 ([::1]:20002/0%0) wireguard: wg0: Sending keepalive packet to peer 61 ([::1]:20002/0%0) wireguard: wg0: Sending keepalive packet to peer 49 ([::1]:20002/0%0) wireguard: wg0: Sending keepalive packet to peer 1 ([::1]:20002/0%0) wireguard: wg1: Sending keepalive packet to peer 40 (127.0.0.1:20003) NMI backtrace for cpu 0 CPU: 0 PID: 7775 Comm: syz.9.837 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:io_serial_in+0x73/0xb0 drivers/tty/serial/8250/8250_port.c:461 Code: e8 22 4d 24 fd 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 c3 80 69 fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 44 89 f9 80 e1 07 38 c1 7c aa 4c RSP: 0018:ffffc900000073b8 EFLAGS: 00000002 RAX: 1ffffffff2cc3d00 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: 0000000000000020 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000e6c R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff9661e8a0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555579f824e8 CR3: 000000002ad12000 CR4: 00000000003506f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:116 [inline] wait_for_xmitr+0xc7/0x240 drivers/tty/serial/8250/8250_port.c:2069 serial8250_console_putchar+0x1a/0x50 drivers/tty/serial/8250/8250_port.c:3315 uart_console_write+0xaa/0x100 drivers/tty/serial/serial_core.c:1981 serial8250_console_write+0xb90/0xf50 drivers/tty/serial/8250/8250_port.c:3392 call_console_drivers kernel/printk/printk.c:-1 [inline] console_unlock+0xb47/0x10f0 kernel/printk/printk.c:2744 vprintk_emit+0xc0/0x150 kernel/printk/printk.c:2274 _printk+0xda/0x130 kernel/printk/printk.c:2299 __dynamic_pr_debug+0x196/0x240 lib/dynamic_debug.c:619 wg_packet_send_keepalive+0x293/0x2b0 drivers/net/wireguard/send.c:234 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648 expire_timers kernel/time/timer.c:1699 [inline] __run_timers+0x56c/0x810 kernel/time/timer.c:1970 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983 handle_softirqs+0x336/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5629 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc900033572a0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 2ce7541bc73d4600 RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a48c0 RBP: ffffc900033573c0 R08: dffffc0000000000 R09: 1ffffffff203e218 R10: dffffc0000000000 R11: fffffbfff203e219 R12: ffffffff8c31ef60 R13: 1ffff9200066ae60 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] lock_page_memcg+0xa5/0x440 mm/memcontrol.c:2047 page_remove_rmap+0x2a/0x10f0 mm/rmap.c:1351 zap_pte_range mm/memory.c:1384 [inline] zap_pmd_range mm/memory.c:1505 [inline] zap_pud_range mm/memory.c:1534 [inline] zap_p4d_range mm/memory.c:1555 [inline] unmap_page_range+0xee4/0x2410 mm/memory.c:1576 unmap_vmas+0x131/0x250 mm/memory.c:1653 exit_mmap+0x3b9/0x640 mm/mmap.c:3216 __mmput+0x115/0x390 kernel/fork.c:1133 exit_mm+0x632/0x7b0 kernel/exit.c:557 do_exit+0x5b8/0x2110 kernel/exit.c:877 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 get_signal+0x7eb/0x12e0 kernel/signal.c:2913 arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:157 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217 __syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:310 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f93f995e159 Code: Unable to access opcode bytes at RIP 0x7f93f995e12f. RSP: 002b:00007f93f7bb60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f93f9be5fa8 RCX: 00007f93f995e159 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f93f9be5fa8 RBP: 00007f93f9be5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f93f9be6038 R14: 00007ffc3def1a70 R15: 00007ffc3def1b58 wireguard: wg0: Retrying handshake with peer 62 ([::1]:20003/0%0) because we stopped hearing back after 15 seconds