INFO: task syz.8.1275:10622 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.1275 state:D stack:25784 pid:10622 tgid:10617 ppid:9358 task_flags:0x400040 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
io_schedule+0xbf/0x130 kernel/sched/core.c:7871
folio_wait_bit_common+0x3d5/0x9e0 mm/filemap.c:1330
folio_lock include/linux/pagemap.h:1141 [inline]
migrate_folio_unmap mm/migrate.c:1241 [inline]
migrate_pages_batch+0x1487/0x3bb0 mm/migrate.c:1882
migrate_pages_sync+0x4c5/0x8a0 mm/migrate.c:2026
migrate_pages+0x1b5f/0x23a0 mm/migrate.c:2108
compact_zone+0x2018/0x4750 mm/compaction.c:2647
compact_node+0x1a3/0x2c0 mm/compaction.c:2916
compact_nodes mm/compaction.c:2938 [inline]
sysctl_compaction_handler mm/compaction.c:2989 [inline]
sysctl_compaction_handler+0x141/0x210 mm/compaction.c:2976
proc_sys_call_handler+0x445/0x570 fs/proc/proc_sysctl.c:600
iter_file_splice_write+0xa24/0x12e0 fs/splice.c:738
do_splice_from fs/splice.c:938 [inline]
direct_splice_actor+0x192/0x6c0 fs/splice.c:1161
splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105
do_splice_direct_actor fs/splice.c:1204 [inline]
do_splice_direct+0x174/0x240 fs/splice.c:1230
do_sendfile+0xb06/0xe50 fs/read_write.c:1370
__do_sys_sendfile64 fs/read_write.c:1425 [inline]
__se_sys_sendfile64 fs/read_write.c:1417 [inline]
__x64_sys_sendfile64+0x154/0x220 fs/read_write.c:1417
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c9eb8f749
RSP: 002b:00007f1c9cdf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f1c9ede6090 RCX: 00007f1c9eb8f749
RDX: 00002000000000c0 RSI: 000000000000000a RDI: 000000000000000b
RBP: 00007f1c9ec13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c9ede6128 R14: 00007f1c9ede6090 R15: 00007ffc155d74b8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c4760 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:6/2963:
#0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
#0: ffff8880b843a398 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
#1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline]
#1: ffff8880b8424088 (psi_seq){-.-.}-{0:0}, at: __schedule+0x1861/0x5de0 kernel/sched/core.c:6923
2 locks held by getty/5572:
#0: ffff8880360210a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
3 locks held by kworker/u8:15/6282:
#0: ffff88813ff29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: raw_spin_rq_lock_nested kernel/sched/core.c:646 [inline]
#0: ffff88813ff29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:631
#1: ffffc9000c6d7d00 ((work_completion)(&utn->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffffffff900e7d48 (rtnl_mutex){+.+.}-{4:4}, at: udp_tunnel_nic_device_sync_work+0x27/0xa10 net/ipv4/udp_tunnel_nic.c:736
1 lock held by udevd/9357:
#0: ffff8881427f2358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:945
3 locks held by kworker/0:2/9485:
#0: ffff88813ff11948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238
#1: ffffc900034c7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239
#2: ffff88804f657240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1b6/0x6da0 drivers/net/netdevsim/fib.c:1490
1 lock held by syz.8.1275/10622:
#0: ffff888078174420 (sb_writers#3){.+.+}-{0:0}, at: splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105
2 locks held by syz.0.1764/12389:
#0: ffff8880362fa0e0 (&type->s_umount_key#95/1){+.+.}-{4:4}, at: alloc_super+0x1e3/0xb60 fs/super.c:344
#1: ffff8881427f2358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xa2/0xe40 block/bdev.c:945
3 locks held by syz-executor/12660:
#0: ffffffff900e7d48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff900e7d48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff900e7d48 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x600/0x2000 net/core/rtnetlink.c:4064
#1: ffff88807645d4e8 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_open+0x1fa/0x4d0 drivers/net/wireguard/device.c:50
#2: ffffffff8e3cfcf8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311
1 lock held by syz.9.1846/12720:
#0: ffffffff8e3cfbc0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3820
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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:332 [inline]
watchdog+0xf3f/0x1170 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 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: 6282 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: udp_tunnel_nic udp_tunnel_nic_device_sync_work
RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:407
Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1c 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d e9 56 43 3a 06 e8 a1 05 fc fc eb a0 e8 2a 06 fc
RSP: 0018:ffffc9000c6d73e0 EFLAGS: 00000002
RAX: 0000000000000038 RBX: 00000000000003f8 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: ffffffff85298415 RDI: ffffffff9addb780
RBP: ffffffff9addb740 R08: 0000000000000001 R09: 000000000000001f
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000038 R14: ffffffff9addb740 R15: ffffffff852983b0
FS: 0000000000000000(0000) GS:ffff888124a05000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb764d7a6b0 CR3: 000000005dce9000 CR4: 00000000003526f0
DR0: 000000000000000a DR1: 0000000000009bfa DR2: 0000000000008000
DR3: 0000000000000005 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
serial_port_out include/linux/serial_core.h:811 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3264 [inline]
serial8250_console_write+0xfbd/0x1890 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3111 [inline]
console_flush_all+0x801/0xc60 kernel/printk/printk.c:3199
__console_flush_and_unlock kernel/printk/printk.c:3258 [inline]
console_unlock+0xd8/0x210 kernel/printk/printk.c:3298
vprintk_emit+0x3d7/0x680 kernel/printk/printk.c:2423
dev_vprintk_emit drivers/base/core.c:4914 [inline]
dev_printk_emit+0xfa/0x140 drivers/base/core.c:4925
__netdev_printk+0x1fb/0x500 net/core/dev.c:12716
netdev_info+0xe4/0x120 net/core/dev.c:12771
nsim_udp_tunnel_set_port+0x250/0x370 drivers/net/netdevsim/udp_tunnels.c:31
udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:228 [inline]
udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:249 [inline]
__udp_tunnel_nic_device_sync.part.0+0x931/0xe40 net/ipv4/udp_tunnel_nic.c:292
__udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:740 [inline]
udp_tunnel_nic_device_sync_work+0xb3/0xa10 net/ipv4/udp_tunnel_nic.c:740
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245