INFO: task syz.8.6211:19364 blocked for more than 122 seconds. Not tainted 6.12.38-syzkaller-gd0c633175c04 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.8.6211 state:D stack:0 pid:19364 tgid:19364 ppid:17638 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5945 [inline] __schedule+0x1322/0x1df0 kernel/sched/core.c:7791 __schedule_loop kernel/sched/core.c:7872 [inline] schedule+0xc6/0x240 kernel/sched/core.c:7887 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x81e/0x1b50 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:285 rcu_barrier+0x4d/0x530 kernel/rcu/tree.c:4589 netdev_run_todo+0x10e/0xcb0 net/core/dev.c:10868 rtnl_unlock+0x12/0x20 net/core/rtnetlink.c:152 tun_detach drivers/net/tun.c:704 [inline] tun_chr_close+0xc5/0x150 drivers/net/tun.c:3517 __fput+0x1fe/0xa00 fs/file_table.c:429 ____fput+0x20/0x30 fs/file_table.c:457 task_work_run+0x1e0/0x250 kernel/task_work.c:240 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x9bc/0x2630 kernel/exit.c:953 do_group_exit+0x22a/0x300 kernel/exit.c:1095 get_signal+0x139d/0x14f0 kernel/signal.c:2933 arch_do_signal_or_restart+0x96/0x720 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x58/0xb0 kernel/entry/common.c:218 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fe493bc14a5 RSP: 002b:00007fe49491ff80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007fe493db5fa0 RCX: 00007fe493bc14a5 RDX: 00007fe49491ffc0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fe493c11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007fe493db6038 R14: 00007fe493db5fa0 R15: 00007fffff988f88 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.38-syzkaller-gd0c633175c04 #0 79f03ae2e0a264f34f505a942aaa3597bcba712e Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120 dump_stack+0x19/0x20 lib/dump_stack.c:129 nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline] watchdog+0xd8f/0xed0 kernel/hung_task.c:423 kthread+0x2ca/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 1 to CPUs 0: bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 46 Comm: kworker/u8:2 Not tainted 6.12.38-syzkaller-gd0c633175c04 #0 79f03ae2e0a264f34f505a942aaa3597bcba712e Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: wg-kex-wg1 wg_packet_handshake_send_worker RIP: 0010:io_serial_in+0x7b/0xc0 drivers/tty/serial/8250/8250_port.c:406 Code: e8 ca ac 6d fe 44 89 f9 d3 e3 49 83 c6 08 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 2b d4 c3 fe 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f 5d e9 c5 ca 75 02 cc 44 89 f9 80 e1 RSP: 0018:ffffc90000007030 EFLAGS: 00000002 RAX: 1ffffffff113d900 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffc90000007050 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff83183010 R12: dffffc0000000000 R13: 00000000000026af R14: ffffffff889ecde8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7594ce7d60 CR3: 00000000072a8000 CR4: 00000000003526b0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:137 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline] wait_for_lsr drivers/tty/serial/8250/8250_port.c:2069 [inline] fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3315 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3337 [inline] serial8250_console_write+0x147a/0x2130 drivers/tty/serial/8250/8250_port.c:3422 univ8250_console_write+0x6f/0xb0 drivers/tty/serial/8250/8250_core.c:396 console_emit_next_record kernel/printk/printk.c:3150 [inline] console_flush_all+0x5e6/0xaa0 kernel/printk/printk.c:3238 __console_flush_and_unlock kernel/printk/printk.c:3297 [inline] console_unlock+0xe9/0x270 kernel/printk/printk.c:3337 vprintk_emit+0x27c/0x640 kernel/printk/printk.c:2461 vprintk_default+0x2a/0x40 kernel/printk/printk.c:2476 vprintk+0x93/0xa0 kernel/printk/printk_safe.c:73 _printk+0xd0/0x120 kernel/printk/printk.c:2486 br_fdb_update+0x604/0x680 net/bridge/br_fdb.c:904 br_handle_frame_finish+0x39c/0x1720 net/bridge/br_input.c:141 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline] br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424 __netif_receive_skb_core+0xf4b/0x3940 net/core/dev.c:5651 __netif_receive_skb_one_core net/core/dev.c:5755 [inline] __netif_receive_skb net/core/dev.c:5870 [inline] process_backlog+0x3e5/0xae0 net/core/dev.c:6206 __napi_poll+0xd3/0x610 net/core/dev.c:6857 napi_poll net/core/dev.c:6926 [inline] net_rx_action+0x584/0xce0 net/core/dev.c:7048 handle_softirqs+0x1ab/0x630 kernel/softirq.c:621 __do_softirq+0xf/0x16 kernel/softirq.c:659 do_softirq+0xa6/0x100 kernel/softirq.c:503 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] mod_peer_timer drivers/net/wireguard/timers.c:38 [inline] wg_timers_handshake_initiated+0x14e/0x190 drivers/net/wireguard/timers.c:184 wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:42 [inline] wg_packet_handshake_send_worker+0x1e0/0x240 drivers/net/wireguard/send.c:51 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3319 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400 kthread+0x2ca/0x370 kernel/kthread.c:389 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:86:48:50:d7:3d:b4, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) net_ratelimit: 69733 callbacks suppressed bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:86:48:50:d7:3d:b4, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:86:48:50:d7:3d:b4, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)