INFO: task kworker/u8:0:11 blocked for more than 143 seconds.
      Not tainted 6.13.0-rc6-next-20250107-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:0    state:D stack:21040 pid:11    tgid:11    ppid:2      flags:0x00004000
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5371 [inline]
 __schedule+0x18f6/0x4cd0 kernel/sched/core.c:6758
 __schedule_loop kernel/sched/core.c:6835 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6850
 bit_wait+0x12/0xd0 kernel/sched/wait_bit.c:237
 __wait_on_bit+0xb0/0x2f0 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x1d5/0x260 kernel/sched/wait_bit.c:64
 wait_on_bit include/linux/wait_bit.h:77 [inline]
 netfs_retry_writes+0x16e/0x19b0 fs/netfs/write_retry.c:215
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x2f90/0x3bb0 fs/netfs/write_collect.c:374
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u8:0/11:
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc90000107c60 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000107c60 ((work_completion)(&rreq->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
1 lock held by khungtaskd/30:
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6746
2 locks held by kworker/u8:8/3545:
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc9000cb17c60 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000cb17c60 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
3 locks held by udevd/5207:
2 locks held by getty/5592:
 #0: ffff888030c0d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
10 locks held by kworker/1:3/5838:
 #0: ffff8881446b2148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff8881446b2148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc90003fcfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90003fcfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffff88802851a190 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1014 [inline]
 #2: ffff88802851a190 (&dev->mutex){....}-{4:4}, at: hub_event+0x1fe/0x5150 drivers/usb/core/hub.c:5851
 #3: ffff88802851d510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3208 [inline]
 #3: ffff88802851d510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5420 [inline]
 #3: ffff88802851d510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5663 [inline]
 #3: ffff88802851d510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5823 [inline]
 #3: ffff88802851d510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x25b9/0x5150 drivers/usb/core/hub.c:5905
 #4: ffff888028119f68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5421 [inline]
 #4: ffff888028119f68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5663 [inline]
 #4: ffff888028119f68 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5823 [inline]
 #4: ffff888028119f68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x25f7/0x5150 drivers/usb/core/hub.c:5905
 #5: ffff8880b873e958 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598
 #6: ffff8880b8728948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x41d/0x7a0 kernel/sched/psi.c:987
 #7: ffff88801d2fa828 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
 #7: ffff88801d2fa828 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xc2/0x1470 kernel/sched/core.c:4207
 #8: ffff8880b873e958 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:598
 #9: ffff8880b8728948 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_change+0xed/0x270 kernel/sched/psi.c:912
1 lock held by syz.4.824/8005:
 #0: ffff888077fb8500 (&ctx->wb_lock){+.+.}-{4:4}, at: netfs_writepages+0xcf/0x9e0 fs/netfs/write_issue.c:558
2 locks held by kworker/u8:11/9679:
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac89148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc9001c3dfc60 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9001c3dfc60 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc6-next-20250107-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline]
 watchdog+0xff6/0x1040 kernel/hung_task.c:397
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5838 Comm: kworker/1:3 Not tainted 6.13.0-rc6-next-20250107-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: usb_hub_wq hub_event
RIP: 0010:io_serial_out+0x7e/0xc0 drivers/tty/serial/8250/8250_port.c:416
Code: fc 89 e9 41 d3 e7 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 6c 86 af fc 44 03 3b 44 89 f0 44 89 fa ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc 89 e9 80 e1 07 38 c1 7c a7
RSP: 0018:ffffc90003fcedd0 EFLAGS: 00000002
RAX: 0000000000000039 RBX: ffffffff9a728080 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 000000000001a5bf RDI: 000000000001a5c0
RBP: 0000000000000000 R08: ffffffff8576029b R09: 1ffff11004974046
R10: dffffc0000000000 R11: ffffffff85760250 R12: dffffc0000000000
R13: ffffffff9a422f25 R14: 0000000000000039 R15: 00000000000003f8
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6bd21452d8 CR3: 00000000325fe000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 serial8250_console_write+0x14ed/0x1ed0 drivers/tty/serial/8250/8250_port.c:3418
 console_emit_next_record kernel/printk/printk.c:3122 [inline]
 console_flush_all+0x869/0xeb0 kernel/printk/printk.c:3210
 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
 console_unlock+0x14f/0x3b0 kernel/printk/printk.c:3309
 vprintk_emit+0x730/0xa10 kernel/printk/printk.c:2432
 dev_vprintk_emit+0x2ae/0x330 drivers/base/core.c:4919
 dev_printk_emit+0xdd/0x120 drivers/base/core.c:4930
 _dev_info+0x122/0x170 drivers/base/core.c:4988
 hub_port_init+0x7bf/0x2670 drivers/usb/core/hub.c:4952
 hub_port_connect drivers/usb/core/hub.c:5452 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5663 [inline]
 port_event drivers/usb/core/hub.c:5823 [inline]
 hub_event+0x2962/0x5150 drivers/usb/core/hub.c:5905
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>