rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4577/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=81125, q=745 ncpus=2)
task:kworker/u8:15   state:R  running task     stack:23528 pid:4577  tgid:4577  ppid:2      task_flags:0x4288160 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__kasan_check_byte+0xa/0x50 mm/kasan/common.c:571
Code: 41 5c 41 5d e9 47 34 00 00 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 41 54 49 89 f4 55 <48> 89 fd 53 e8 fd 24 00 00 89 c3 84 c0 74 0b 89 d8 5b 5d 41 5c c3
RSP: 0018:ffffc9000e7674f8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff8e3c9620 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff826a4064 RDI: ffffffff8e3c9620
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: ffff8880346a0b30 R12: ffffffff826a4064
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 kasan_check_byte include/linux/kasan.h:401 [inline]
 lock_acquire kernel/locking/lockdep.c:5842 [inline]
 lock_acquire+0xfc/0x330 kernel/locking/lockdep.c:5825
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 kernfs_root+0x34/0x2a0 fs/kernfs/kernfs-internal.h:75
 kernfs_root_is_locked fs/kernfs/kernfs-internal.h:109 [inline]
 kernfs_parent fs/kernfs/kernfs-internal.h:133 [inline]
 __kernfs_remove+0x668/0x920 fs/kernfs/dir.c:1486
 kernfs_remove_by_name_ns+0x68/0x100 fs/kernfs/dir.c:1720
 kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
 remove_files+0x96/0x1c0 fs/sysfs/group.c:28
 sysfs_remove_group+0x8b/0x1b0 fs/sysfs/group.c:328
 sysfs_remove_groups fs/sysfs/group.c:352 [inline]
 sysfs_remove_groups+0x60/0xa0 fs/sysfs/group.c:344
 device_remove_groups drivers/base/core.c:2843 [inline]
 device_remove_attrs+0x203/0x290 drivers/base/core.c:2979
 device_del+0x38e/0x9f0 drivers/base/core.c:3877
 unregister_netdevice_many_notify+0x151e/0x2590 net/core/dev.c:12416
 unregister_netdevice_many net/core/dev.c:12444 [inline]
 default_device_exit_batch+0x995/0xc80 net/core/dev.c:13036
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x363/0xab0 net/core/net_namespace.c:252
 cleanup_net+0x41b/0x830 net/core/net_namespace.c:696
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 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 10542 jiffies! g81125 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:27936 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 06 60 02 c3 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 13 59 13 00 fb f4 <e9> cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0000:ffffffff8e007df8 EFLAGS: 000002c6
RAX: 0000000003a711bd RBX: 0000000000000000 RCX: ffffffff8b7706d9
RDX: 0000000000000000 RSI: ffffffff8dac200a RDI: ffffffff8bf24280
RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d
R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000
R13: ffffffff8e097b40 R14: ffffffff9087f7d0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124909000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33e22ff8 CR3: 0000000075ed9000 CR4: 00000000003526f0
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+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x38d/0x510 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 rest_init+0x16b/0x2b0 init/main.c:757
 start_kernel+0x3ef/0x4d0 init/main.c:1206
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x148
 </TASK>