INFO: task kworker/u8:11:1832 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:11 state:D stack:21280 pid:1832 tgid:1832 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-7:3)
Call Trac[ 2235.045689][ T38] Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
io_schedule+0x80/0xe0 kernel/sched/core.c:7835
folio_wait_bit_common+0x6dd/0xbc0 mm/filemap.c:1323
folio_lock include/linux/pagemap.h:1159 [inline]
writeback_get_folio mm/page-writeback.c:2418 [inline]
writeback_iter+0x8d8/0x12c0 mm/page-writeback.c:2512
mpage_writepages+0x11d/0x1cb0 fs/mpage.c:669
do_writepages+0x32e/0x550 mm/page-writeback.c:2554
__writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1762
writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2054
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241
wb_check_old_data_flush fs/fs-writeback.c:2345 [inline]
wb_do_writeback fs/fs-writeback.c:2398 [inline]
wb_workfn+0xb52/0xf60 fs/fs-writeback.c:2426
process_one_work kernel/workqueue.c:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
4 locks held by kworker/u8:1/13:
#0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff88801aee1138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
#2: ffffffff8f14e380 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x800 net/core/net_namespace.c:675
#3: ffff888057541838 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_destruct+0x116/0x310 drivers/net/wireguard/device.c:249
1 lock held by khungtaskd/38:
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
6 locks held by kworker/u8:8/1392:
3 locks held by kworker/u8:10/1492:
3 locks held by kworker/u8:11/1832:
#0: ffff88801e697138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#0: ffff88801e697138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359
#1: ffffc900067d7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline]
#1: ffffc900067d7c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359
#2: ffff8880362420d0 (&type->s_umount_key#60){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
2 locks held by getty/5563:
#0: ffff888037daf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
7 locks held by udevd/25053:
1 lock held by udevd/25098:
#0: ffff88802260e5f0 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
#0: ffff88802260e5f0 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:854
3 locks held by syz.3.2510/25395:
2 locks held by syz-executor/25554:
#0: ffff8880b292a0d0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880b292a0d0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880b292a0d0 (&type->s_umount_key#32){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
#1: ffffffff8ddd1b70 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3828
3 locks held by syz-executor/26964:
1 lock held by syz.6.2827/27190:
#0: ffff88803c9220d0 (&type->s_umount_key#109/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
2 locks held by syz.7.2829/27202:
2 locks held by udevadm/27224:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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:161 [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:346 [inline]
watchdog+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 26964 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4869 [inline]
RIP: 0010:__lock_acquire+0x46a/0x2cf0 kernel/locking/lockdep.c:5187
Code: 0b 00 00 41 8d 4c 24 ff 83 f9 ff 41 bd ff ff ff ff 44 0f 4c e9 41 ff c5 41 8d 5c 24 01 49 ff cc 89 d9 83 c1 fe 78 40 45 89 e7 <41> 81 e7 ff ff ff 7f 83 f9 31 73 1d 4b 8d 0c bf 41 8b 8c ce d8 0b
RSP: 0018:ffffc90006cb6590 EFLAGS: 00000013
RAX: 000000000002000b RBX: 0000000000000003 RCX: 0000000000000001
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88805ffd2ab0 R08: ffffffff82649d9c R09: ffffffff8ddcb9c0
R10: dffffc0000000000 R11: fffffbfff1ed4d57 R12: 0000000000000001
R13: 0000000000000000 R14: ffff88805ffd1e80 R15: 0000000000000001
FS: 000055557d2fd500(0000) GS:ffff888126436000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9da31a7000 CR3: 000000003214c000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
kernfs_root+0x38/0x230 fs/kernfs/kernfs-internal.h:75
kernfs_root_is_locked fs/kernfs/kernfs-internal.h:109 [inline]
kernfs_rcu_name fs/kernfs/kernfs-internal.h:119 [inline]
kernfs_sd_compare fs/kernfs/dir.c:349 [inline]
kernfs_link_sibling+0xed/0x540 fs/kernfs/dir.c:380
kernfs_add_one+0x1ca/0x5c0 fs/kernfs/dir.c:815
__kernfs_create_file+0x22b/0x2e0 fs/kernfs/file.c:1086
sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:313
create_files fs/sysfs/group.c:82 [inline]
internal_create_group+0x673/0x1180 fs/sysfs/group.c:189
internal_create_groups fs/sysfs/group.c:229 [inline]
sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255
device_add_groups drivers/base/core.c:2837 [inline]
device_add_attrs+0xdd/0x5b0 drivers/base/core.c:2901
device_add+0x496/0xb80 drivers/base/core.c:3645
netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2358
register_netdevice+0x12d7/0x1d10 net/core/dev.c:11436
veth_newlink+0x4a4/0xb70 drivers/net/veth.c:1860
rtnl_newlink_create+0x329/0xb70 net/core/rtnetlink.c:3862
__rtnl_newlink net/core/rtnetlink.c:3979 [inline]
rtnl_newlink+0x1666/0x1be0 net/core/rtnetlink.c:4094
rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6980
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x831/0x9f0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
__sys_sendto+0x67f/0x710 net/socket.c:2206
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2209
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcfd895d04e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ffdb4ddc208 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055557d2fd500 RCX: 00007fcfd895d04e
RDX: 000000000000008c RSI: 00007fcfd9744670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffdb4ddc284 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fcfd9744670 R15: 0000000000000000