rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6489/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=44709, q=471 ncpus=2)
task:kworker/1:10    state:R  running task     stack:21024 pid:6489  tgid:6489  ppid:2      task_flags:0x4288060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5030 kernel/sched/core.c:6864
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:121 [inline]
RIP: 0010:lock_release+0x67/0x3d0 kernel/locking/lockdep.c:5881
Code: 0f a3 05 6c 44 df 0d 73 0d e8 a5 1c 09 00 84 c0 0f 84 ad 02 00 00 83 3d 86 74 df 0d 00 0f 84 44 02 00 00 65 8b 05 89 fe d7 10 <85> c0 0f 85 35 02 00 00 65 4c 8b 3c 25 08 60 76 92 41 83 bf 2c 0b
RSP: 0018:ffffc90003dff3e8 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff8264b22c RCX: fb52b9ca441b6000
RDX: ffffc90019936000 RSI: ffffffff8bbf81c0 RDI: ffffffff8bbf8180
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8264b22c
R10: dffffc0000000000 R11: ffffed100f108279 R12: dffffc0000000000
R13: ffffffff8264b22c R14: ffffffff8df3d980 R15: ffff88805ea2dc30
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:897 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 kernfs_root+0x1e5/0x230 fs/kernfs/kernfs-internal.h:80
 __kernfs_remove+0x54/0x650 fs/kernfs/dir.c:1477
 kernfs_remove_by_name_ns+0xaf/0x130 fs/kernfs/dir.c:1717
 kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
 remove_files fs/sysfs/group.c:31 [inline]
 sysfs_remove_group+0x1d1/0x2f0 fs/sysfs/group.c:322
 sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:346
 device_remove_groups drivers/base/core.c:2899 [inline]
 device_remove_attrs+0x1aa/0x260 drivers/base/core.c:3029
 device_del+0x509/0x8e0 drivers/base/core.c:3933
 usb_disconnect+0x615/0x990 drivers/usb/core/hub.c:2376
 hub_port_connect drivers/usb/core/hub.c:5407 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x1ca9/0x4ef0 drivers/usb/core/hub.c:5953
 process_one_work+0x93a/0x15e0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: rcu_preempt kthread starved for 10510 jiffies! g44709 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27104 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5257 [inline]
 __schedule+0x14bc/0x5030 kernel/sched/core.c:6864
 __schedule_loop kernel/sched/core.c:6946 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6961
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 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 33 70 0c 00 f3 0f 1e fa fb f4 <e9> c8 f2 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: 5a95dab5774da100 RBX: ffffffff8197acb7 RCX: 5a95dab5774da100
RDX: 0000000000000001 RSI: ffffffff8d78f71d RDI: ffffffff8bbf81e0
RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db
R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f7deb70
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11003a5eb70
FS:  0000000000000000(0000) GS:ffff888125fba000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3450eff8 CR3: 0000000030d2c000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 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:767
 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e7/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x147
 </TASK>