rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=9b44/1/0x4000000000000000 softirq=23662/23662 fqs=0
rcu: 	(detected by 0, t=10505 jiffies, g=14997, q=859 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7289 Comm: syz.4.381 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:__lock_acquire+0x6e2/0xd20
Code: 18 00 75 13 48 63 44 24 20 48 0f a3 05 a7 29 0b 12 0f 83 15 05 00 00 31 ed 48 8b 3c 24 4c 8b bf e0 0a 00 00 48 83 7c 24 28 00 <75> 1e 83 3d 05 b9 0e 18 00 0f 95 c0 49 83 ff ff 0f 94 c1 08 c1 bd
RSP: 0018:ffffc900001e0750 EFLAGS: 00000002
RAX: 0000000000000067 RBX: 0000000000000001 RCX: ffffffff9349f388
RDX: 0000000000000008 RSI: ffff88810e1c6180 RDI: ffff88810e1c5640
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81ada78b
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: 0000000000000002
R13: 0000000000000002 R14: ffff88810e1c6180 R15: 64d322f6df38f518
FS:  00007f57b7bf66c0(0000) GS:ffff8881a3c12000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001239f2000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 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+0x3c5/0x550
 __hrtimer_run_queues+0x4e0/0xc60
 hrtimer_interrupt+0x45b/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:lock_acquire+0x175/0x360
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 7b 6f 03 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc900044af6c0 EFLAGS: 00000206
RAX: 49a8a2a0952b6900 RBX: 0000000000000000 RCX: 49a8a2a0952b6900
RDX: 0000000000000000 RSI: ffffffff8dbaa0c3 RDI: ffffffff8be34280
RBP: ffffffff822eda4a R08: 0000000000000000 R09: ffffffff822eda4a
R10: dffffc0000000000 R11: ffffed100759fe1a R12: 0000000000000002
R13: ffffffff8e13a120 R14: 0000000000000000 R15: 0000000000000246
 __page_table_check_zero+0xd7/0x530
 post_alloc_hook+0x253/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 ___kmalloc_large_node+0x5f/0x1b0
 __kmalloc_large_node_noprof+0x18/0x90
 __kvmalloc_node_noprof+0x6d/0x5f0
 alloc_netdev_mqs+0xc7c/0x11b0
 tun_set_iff+0x532/0xef0
 __tun_chr_ioctl+0x788/0x1df0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f57b6d8ec29
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:00007f57b7bf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f57b6fd5fa0 RCX: 00007f57b6d8ec29
RDX: 0000200000000080 RSI: 00000000400454ca RDI: 0000000000000004
RBP: 00007f57b6e11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f57b6fd6038 R14: 00007f57b6fd5fa0 R15: 00007ffd21e52348
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g14997 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=5176
rcu: rcu_preempt kthread starved for 10505 jiffies! g14997 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
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+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
