syzbot

INFO: task kworker/1:6:5913 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:6     state:D stack:20824 pid:5913  tgid:5913  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1b88/0x5240 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 __mutex_lock_common kernel/locking/mutex.c:678 [inline]
 __mutex_lock+0x805/0x10c0 kernel/locking/mutex.c:746
 hub_port_connect drivers/usb/core/hub.c:5429 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5671 [inline]
 port_event drivers/usb/core/hub.c:5831 [inline]
 hub_event+0x24cd/0x50f0 drivers/usb/core/hub.c:5913
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd50 kernel/workqueue.c:3400
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8ed3dfa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8ed3dfa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8ed3dfa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x30/0x180 kernel/locking/lockdep.c:6764
2 locks held by kworker/u8:2/36:
2 locks held by kworker/u8:4/64:
 #0: ffff888140501148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff888140501148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc90001567c60 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90001567c60 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
3 locks held by kworker/u8:6/1151:
 #0: ffff888140501148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff888140501148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc900040bfc60 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc900040bfc60 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffffffff8ed434b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
 #2: ffffffff8ed434b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x384/0x830 kernel/rcu/tree_exp.h:998
2 locks held by kworker/u8:7/2978:
2 locks held by getty/5594:
 #0: ffff8880363620a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x5bb/0x1700 drivers/tty/n_tty.c:2222
5 locks held by kworker/0:3/5839:
 #0: ffff888020e91948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff888020e91948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc90003edfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90003edfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffff888145789198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #2: ffff888145789198 (&dev->mutex){....}-{4:4}, at: hub_event+0x200/0x50f0 drivers/usb/core/hub.c:5859
 #3: ffff88814578c510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3220 [inline]
 #3: ffff88814578c510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5428 [inline]
 #3: ffff88814578c510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5671 [inline]
 #3: ffff88814578c510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5831 [inline]
 #3: ffff88814578c510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2494/0x50f0 drivers/usb/core/hub.c:5913
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5429 [inline]
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5671 [inline]
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5831 [inline]
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x24cd/0x50f0 drivers/usb/core/hub.c:5913
4 locks held by udevd/5893:
 #0: ffff88805e0a40a0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb4/0xda0 fs/seq_file.c:182
 #1: ffff8880287b1488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x53/0x3b0 fs/kernfs/file.c:154
 #2: ffff888035288698 (kn->active#20){++++}-{0:0}, at: kernfs_seq_start+0x72/0x3b0 fs/kernfs/file.c:155
 #3: ffff88814d0f9198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:927 [inline]
 #3: ffff88814d0f9198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
5 locks held by kworker/1:6/5913:
 #0: ffff888020e91948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff888020e91948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc9000439fc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc9000439fc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffff888029959198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #2: ffff888029959198 (&dev->mutex){....}-{4:4}, at: hub_event+0x200/0x50f0 drivers/usb/core/hub.c:5859
 #3: ffff88802995c510 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3220 [inline]
 #3: ffff88802995c510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5428 [inline]
 #3: ffff88802995c510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5671 [inline]
 #3: ffff88802995c510 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5831 [inline]
 #3: ffff88802995c510 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2494/0x50f0 drivers/usb/core/hub.c:5913
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5429 [inline]
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5671 [inline]
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5831 [inline]
 #4: ffff888143be2b68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x24cd/0x50f0 drivers/usb/core/hub.c:5913
4 locks held by kworker/0:7/5918:
 #0: ffff888020e91948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff888020e91948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x990/0x18e0 kernel/workqueue.c:3319
 #1: ffffc900043dfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc900043dfc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9cb/0x18e0 kernel/workqueue.c:3319
 #2: ffff888028b35198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #2: ffff888028b35198 (&dev->mutex){....}-{4:4}, at: hub_event+0x200/0x50f0 drivers/usb/core/hub.c:5859
 #3: ffff88814d0f9198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:922 [inline]
 #3: ffff88814d0f9198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x90/0x530 drivers/base/dd.c:1005
3 locks held by kworker/u8:3/10704:
 #0: ffff8880b8639b18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xb0/0x140 kernel/sched/core.c:613
 #1: ffff8880b8723b08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x41f/0x7a0 kernel/sched/psi.c:987
 #2: ffffffff9a96bb90 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_deactivate+0x164/0x390 lib/debugobjects.c:873

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x4ab/0x4e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0x1058/0x10a0 kernel/hung_task.c:437
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.15.0-rc2-syzkaller-00042-g1a1d569a75f3 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 60 17 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197dc0 EFLAGS: 000002c6
RAX: 49720f59aaa8eb00 RBX: ffffffff8197aebe RCX: ffffffff8c30d95c
RDX: 0000000000000001 RSI: ffffffff8e69d04f RDI: ffffffff8ca1b760
RBP: ffffc90000197f20 R08: ffff8880b8732b5b R09: 1ffff110170e656b
R10: dffffc0000000000 R11: ffffed10170e656c R12: 1ffff92000032fd2
R13: 1ffff11003ad9b40 R14: 0000000000000001 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125093000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404030 CR3: 000000007d8c8000 CR4: 00000000003526f0
DR0: 0000000000000007 DR1: ffffffffffffffff DR2: 0000000000000008
DR3: 1000000100000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x22e/0x5d0 kernel/sched/idle.c:325
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
 start_secondary+0xfe/0x100 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x147
 </TASK>