rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10506 jiffies, g=116217, q=341 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10506 (4295032702-4295022196), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g116217 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=48922
rcu: rcu_preempt kthread starved for 10506 jiffies! g116217 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->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 stack:27208 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x12b/0x270
 rcu_gp_fqs_loop+0x301/0x1540
 rcu_gp_kthread+0x99/0x390
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </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: 22074 Comm: syz.9.4467 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:mark_lock+0x2b/0x190
Code: 41 57 41 56 41 55 41 54 53 8b 46 20 89 c1 81 e1 00 00 03 00 83 f9 01 bb 09 00 00 00 83 db 00 83 fa 08 0f 45 da bd 01 00 00 00 <89> d9 d3 e5 25 ff 1f 00 00 48 0f a3 05 64 66 2b 12 73 10 48 69 c0
RSP: 0018:ffffc900001e0018 EFLAGS: 00000097
RAX: 00000000000c6068 RBX: 0000000000000004 RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffff888021cf62a8 RDI: ffff888021cf5700
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81ae2edb
R10: dffffc0000000000 R11: ffffed1026cc4f59 R12: 0000000000000002
R13: 0000000000000002 R14: ffff888021cf62a8 R15: 0000000000000000
FS:  00007f298c4e56c0(0000) GS:ffff8881a3a03000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdd5c4b7fc8 CR3: 000000003916a000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __lock_acquire+0x680/0xd20
 lock_acquire+0x120/0x360
 _raw_spin_lock_irqsave+0xa7/0xf0
 hrtimer_try_to_cancel+0x22b/0x420
 hrtimer_cancel+0x3b/0x50
 cpu_clock_event_stop+0xd9/0x130
 __perf_event_overflow+0x580/0xe40
 perf_swevent_hrtimer+0x3b8/0x500
 __hrtimer_run_queues+0x4e0/0xc60
 hrtimer_interrupt+0x45b/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0x52/0xc0
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110
Code: 74 05 e8 3b 1a 47 f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 23 b5 0f f6 65 8b 05 dc e8 40 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc900001e09e0 EFLAGS: 00000206
RAX: 72a7e5b5c1251500 RBX: 0000000000000a06 RCX: 72a7e5b5c1251500
RDX: 0000000000000002 RSI: ffffffff8db9e917 RDI: 0000000000000001
RBP: ffffc900001e0a70 R08: ffffffff8fc34377 R09: 1ffffffff1f8686e
R10: dffffc0000000000 R11: fffffbfff1f8686f R12: dffffc0000000000
R13: ffff888105984960 R14: ffffffff99ed49a8 R15: 1ffff9200003c13c
 debug_check_no_obj_freed+0x451/0x470
 kfree+0x115/0x6d0
 slab_free_after_rcu_debug+0x60/0x2a0
 rcu_core+0xcab/0x1770
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:finish_task_switch+0x2b3/0x950
Code: a4 24 5b 16 00 00 bf 49 8d 9c 24 b8 16 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 4c 8b 7d b8 0f 85 04 03 00 00 83 3b 00 <0f> 85 c0 00 00 00 0f 1f 44 00 00 4d 85 ff 74 72 49 81 c4 98 05 00
RSP: 0018:ffffc900035f71d8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888021cf6db8 RCX: 72a7e5b5c1251500
RDX: 0000000000000006 RSI: ffffffff8db9e917 RDI: ffff888021cf6d58
RBP: ffffc900035f7230 R08: ffffffff8fc34377 R09: 1ffffffff1f8686e
R10: dffffc0000000000 R11: fffffbfff1f8686f R12: ffff888021cf5700
R13: dffffc0000000000 R14: ffff888106bed700 R15: 0000000000000000
 __schedule+0x17a0/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x872/0xfe0
 down_write+0x1ab/0x1f0
 kernfs_add_one+0x2c2/0x520
 __kernfs_create_file+0x22b/0x2e0
 sysfs_add_file_mode_ns+0x238/0x300
 internal_create_group+0x66d/0x1110
 sysfs_create_groups+0x59/0x120
 device_add_attrs+0x1c4/0x5a0
 device_add+0x496/0xb50
 netdev_register_kobject+0x178/0x310
 register_netdevice+0x126c/0x1ae0
 tun_set_iff+0x844/0xf00
 __tun_chr_ioctl+0x795/0x1e10
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f298b58ec29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f298c4e5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f298b7d5fa0 RCX: 00007f298b58ec29
RDX: 00002000000000c0 RSI: 00000000400454ca RDI: 0000000000000008
RBP: 00007f298b611e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f298b7d6038 R14: 00007f298b7d5fa0 R15: 00007fff4d2b0678
 </TASK>
