INFO: task syz.0.6223:3800 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.6223 state:D stack:28920 pid:3800 tgid:3799 ppid:490 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7322
cgroup_lock_and_drain_offline+0x51a/0x650 kernel/cgroup/cgroup.c:3275
cgroup1_get_tree+0x9d/0x890 kernel/cgroup/cgroup-v1.c:1265
vfs_get_tree+0x92/0x2a0 fs/super.c:1694
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3765 [inline]
do_new_mount+0x319/0xdc0 fs/namespace.c:3841
do_mount fs/namespace.c:4174 [inline]
__do_sys_mount fs/namespace.c:4390 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4367
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f69a439ce59
RSP: 002b:00007f69a525f028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f69a4615fa0 RCX: 00007f69a439ce59
RDX: 00002000000000c0 RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007f69a4432e6f R08: 00002000000001c0 R09: 0000000000000000
R10: 0000000000010012 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f69a4616038 R14: 00007f69a4615fa0 R15: 00007ffe82652618
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
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: 31794 Comm: kworker/u8:23 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: netns cleanup_net
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:401
Code: e8 6e 6f 7d fc 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 cf 8d ea fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 05 8f c7 fb cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90005e1e8b8 EFLAGS: 00000006
RAX: 1ffffffff34fa005 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc90005e1ea50 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8548b180 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff9a7d05c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812525d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557ab2a81f40 CR3: 0000000021794000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
serial_port_in include/linux/serial_core.h:806 [inline]
serial8250_console_write+0x547/0x1bd0 drivers/tty/serial/8250/8250_port.c:3324
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record kernel/printk/printk.c:3269 [inline]
console_flush_all+0x6ea/0xaf0 kernel/printk/printk.c:3343
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
dev_vprintk_emit+0x338/0x400 drivers/base/core.c:4996
dev_printk_emit+0xee/0x140 drivers/base/core.c:5007
__netdev_printk+0x3e1/0x480 net/core/dev.c:12956
netdev_info+0x11e/0x180 net/core/dev.c:13011
nsim_udp_tunnel_unset_port+0x2bd/0x520 drivers/net/netdevsim/udp_tunnels.c:59
udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline]
udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:249 [inline]
__udp_tunnel_nic_device_sync+0xb62/0x1560 net/ipv4/udp_tunnel_nic.c:292
udp_tunnel_nic_flush+0x2d1/0x670 net/ipv4/udp_tunnel_nic.c:694
udp_tunnel_nic_unregister net/ipv4/udp_tunnel_nic.c:901 [inline]
udp_tunnel_nic_netdevice_event+0x1073/0x1850 net/ipv4/udp_tunnel_nic.c:942
notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2288 [inline]
call_netdevice_notifiers net/core/dev.c:2302 [inline]
unregister_netdevice_many_notify+0x17de/0x2150 net/core/dev.c:12438
unregister_netdevice_many net/core/dev.c:12499 [inline]
unregister_netdevice_queue+0x2f5/0x340 net/core/dev.c:12311
unregister_netdevice include/linux/netdevice.h:3462 [inline]
nsim_destroy+0x26d/0x800 drivers/net/netdevsim/netdev.c:1194
__nsim_dev_port_del+0x14e/0x200 drivers/net/netdevsim/dev.c:1547
nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1561 [inline]
nsim_dev_reload_destroy+0x288/0x490 drivers/net/netdevsim/dev.c:1785
nsim_dev_reload_down+0x8a/0xc0 drivers/net/netdevsim/dev.c:1038
devlink_reload+0x1c5/0x890 net/devlink/dev.c:462
devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:560
ops_pre_exit_list net/core/net_namespace.c:161 [inline]
ops_undo_list+0x17d/0x8d0 net/core/net_namespace.c:234
cleanup_net+0x572/0x810 net/core/net_namespace.c:702
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245