rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P936/1:b..l..
rcu: 	(detected by 1, t=10502 jiffies, g=12841, q=470 ncpus=2)
task:kworker/0:2     state:R  running task     stack:21864 pid:936   tgid:936   ppid:2      task_flags:0x4288060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5583 [inline]
 __schedule+0x125e/0x6990 kernel/sched/core.c:7382
 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:7662
 irqentry_exit_cond_resched arch/x86/include/asm/fred.h:105 [inline]
 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:453 [inline]
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:543 [inline]
 irqentry_exit+0x33f/0xab0 kernel/entry/common.c:154
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5947
Code: 05 8f 1f cf 13 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 9e 66 80 10 0f 82 c9 02 00 00 8b 35 7e 96 80 10 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 2d 1f cf 13 0f 85 09 03 00 00 48 83 c4
RSP: 0018:ffffc90004ab7270 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000200
RDX: 0000000000000000 RSI: ffffffff8e5f56e3 RDI: ffffffff8c831080
RBP: ffffffff8ffeb520 R08: 000000004c337656 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000001 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
 unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
 __call_rcu_common.constprop.0+0x7b/0x2b0 kernel/rcu/tree.c:3287
 kernfs_put.part.0+0x3a6/0xaa0 fs/kernfs/dir.c:620
 kernfs_put fs/kernfs/dir.c:1786 [inline]
 kernfs_remove_by_name_ns+0xf3/0x120 fs/kernfs/dir.c:1797
 sysfs_remove_file include/linux/sysfs.h:780 [inline]
 device_remove_file drivers/base/core.c:3146 [inline]
 device_remove_file drivers/base/core.c:3142 [inline]
 device_del+0x361/0x9b0 drivers/base/core.c:3963
 device_unregister+0x1d/0xe0 drivers/base/core.c:4006
 usb_remove_ep_devs+0x42/0x90 drivers/usb/core/endpoint.c:181
 remove_intf_ep_devs drivers/usb/core/message.c:1326 [inline]
 usb_disable_device+0x319/0x810 drivers/usb/core/message.c:1483
 usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2355
 hub_port_connect drivers/usb/core/hub.c:5425 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
 port_event drivers/usb/core/hub.c:5889 [inline]
 hub_event+0x1bb1/0x4420 drivers/usb/core/hub.c:5971
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
 process_scheduled_works kernel/workqueue.c:3578 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread starved for 10432 jiffies! g12841 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27400 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5583 [inline]
 __schedule+0x125e/0x6990 kernel/sched/core.c:7382
 __schedule_loop kernel/sched/core.c:7459 [inline]
 schedule+0xdd/0x2c0 kernel/sched/core.c:7474
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x930 kernel/rcu/tree.c:2122
 rcu_gp_kthread+0x179/0x260 kernel/rcu/tree.c:2330
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
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 08/05/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: f7 a4 02 e9 83 63 03 00 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 03 ee 21 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197e00 EFLAGS: 00000246
RAX: 0000000000085781 RBX: ffff88801fe92580 RCX: ffffffff8be9d325
RDX: 0000000000000001 RSI: ffffffff8e61c5eb RDI: ffffffff8c831080
RBP: ffffed1003fd24b0 R08: 0000000000000001 R09: ffffed1017026825
R10: ffff8880b813412b R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88812259c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9c3a0d9dbc CR3: 00000000764a5000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
 default_idle+0x9/0x10 arch/x86/kernel/process.c:768
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x3ae/0x5b0 kernel/sched/idle.c:355
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x158
 </TASK>