INFO: task udevd:5001 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:23688 pid:5001 tgid:5001 ppid:4989 task_flags:0x400140 flags:0x00080000
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
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
wait_for_reconnect drivers/block/nbd.c:1107 [inline]
nbd_handle_cmd drivers/block/nbd.c:1149 [inline]
nbd_queue_rq+0x889/0x1150 drivers/block/nbd.c:1207
blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2117
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xd36/0x1580 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2356
blk_mq_dispatch_list+0xd11/0xe10 include/linux/spinlock.h:-1
blk_mq_flush_plug_list+0x45f/0x540 block/blk-mq.c:2966
__blk_flush_plug+0x3ed/0x4d0 block/blk-core.c:1273
blk_finish_plug block/blk-core.c:1300 [inline]
__submit_bio+0x465/0x560 block/blk-core.c:690
__submit_bio_noacct_mq block/blk-core.c:763 [inline]
submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:797
bh_submit fs/buffer.c:1239 [inline]
block_read_full_folio+0x581/0x810 fs/buffer.c:2449
filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2513
do_read_cache_folio+0x354/0x590 mm/filemap.c:4118
read_mapping_folio include/linux/pagemap.h:1017 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:724
adfspart_check_ICS+0xb1/0x960 block/partitions/acorn.c:357
check_partition block/partitions/core.c:143 [inline]
blk_add_partitions block/partitions/core.c:591 [inline]
bdev_disk_changed+0x851/0x17a0 block/partitions/core.c:695
blkdev_get_whole+0x372/0x510 block/bdev.c:751
bdev_open+0x324/0xd70 block/bdev.c:960
blkdev_open+0x461/0x600 block/fops.c:672
do_dentry_open+0x816/0x1380 fs/open.c:947
vfs_open+0x3b/0x340 fs/open.c:1079
do_open fs/namei.c:4700 [inline]
path_openat+0x2e44/0x3830 fs/namei.c:4859
do_file_open+0x23e/0x4a0 fs/namei.c:4888
do_sys_openat2+0x115/0x200 fs/open.c:1395
do_sys_open fs/open.c:1401 [inline]
__do_sys_openat fs/open.c:1417 [inline]
__se_sys_openat fs/open.c:1412 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1412
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: 0033:0x7fef4d4a7407
RSP: 002b:00007ffe146d1260 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fef4db54880 RCX: 00007fef4d4a7407
RDX: 00000000000a0800 RSI: 0000564f44d3c360 RDI: ffffffffffffff9c
RBP: 0000564f44c7b910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000564f44c93e00
R13: 0000564f44c89190 R14: 0000000000000000 R15: 0000564f44c93e00
INFO: lockdep is turned off.
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 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: 8472 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: bond0 bond_alb_monitor
RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:408
Code: 46 81 fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 6c 9b ec fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90004106830 EFLAGS: 00000002
RAX: 0000000000000035 RBX: 0000000000000035 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: ffff888140ef0237 R09: 1ffff110281de046
R10: dffffc0000000000 R11: ffffffff8544aee0 R12: dffffc0000000000
R13: ffffffff9a499aca R14: ffffffff9a7afc60 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812527c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f61bc9ec4b8 CR3: 000000007b5d0000 CR4: 00000000003526f0
Call Trace:
serial_port_out include/linux/serial_core.h:811 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3220 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
serial8250_console_write+0x1438/0x1bd0 drivers/tty/serial/8250/8250_port.c:3360
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
_printk+0xdd/0x130 kernel/printk/printk.c:2504
gred_dequeue+0x498/0x670 net/sched/sch_gred.c:273
dequeue_skb net/sched/sch_generic.c:322 [inline]
qdisc_restart net/sched/sch_generic.c:427 [inline]
__qdisc_run+0x24c/0x1620 net/sched/sch_generic.c:445
qdisc_run include/net/pkt_sched.h:120 [inline]
__dev_xmit_skb net/core/dev.c:4294 [inline]
__dev_queue_xmit+0x1c00/0x37f0 net/core/dev.c:4833
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x337/0x540 net/ipv6/ip6_output.c:246
ip6tunnel_xmit include/net/ip6_tunnel.h:174 [inline]
udp_tunnel6_xmit_skb+0x6c1/0xd40 net/ipv6/ip6_udp_tunnel.c:112
geneve6_xmit_skb drivers/net/geneve.c:1515 [inline]
geneve_xmit+0x20a5/0x32d0 drivers/net/geneve.c:1546
__netdev_start_xmit include/linux/netdevice.h:5387 [inline]
netdev_start_xmit include/linux/netdevice.h:5396 [inline]
xmit_one net/core/dev.c:3889 [inline]
dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3905
__dev_queue_xmit+0x1435/0x37f0 net/core/dev.c:4872
dev_queue_xmit include/linux/netdevice.h:3436 [inline]
alb_send_lp_vid+0x348/0x550 drivers/net/bonding/bond_alb.c:949
alb_send_learning_packets+0x12c/0x300 drivers/net/bonding/bond_alb.c:1012
bond_alb_monitor+0x3d0/0x17c0 drivers/net/bonding/bond_alb.c:1563
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478
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