rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=be54/1/0x4000000000000000 softirq=77839/77839 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=74521, q=236 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 18558 Comm: syz.4.3578 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+0x58/0x360
Code: 8b 05 fc d2 23 11 48 89 44 24 58 0f 1f 44 00 00 65 8b 05 ff d2 23 11 83 f8 08 0f 83 b8 01 00 00 89 c0 48 0f a3 05 28 46 25 0e <73> 16 e8 f1 f9 08 00 84 c0 75 0d f6 05 2c 2b 0f 0e 01 0f 84 d7 01
RSP: 0018:ffffc900001e07e0 EFLAGS: 00000097
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888136627ad8
RBP: ffffffff81ae2edb R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1026cc4f59 R12: 0000000000000000
R13: ffff888136627ad8 R14: 0000000000000000 R15: 0000000000000001
FS:  00007f188d61a6c0(0000) GS:ffff8881a3a03000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f188c9d7dac CR3: 000000003e508000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 _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+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:lock_release+0x2b5/0x3e0
Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 4b bf 23 11 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90002b4f928 EFLAGS: 00000206
RAX: 6d87bd1578002700 RBX: 0000000000000283 RCX: 6d87bd1578002700
RDX: 0000000000000000 RSI: ffffffff8dd8c926 RDI: ffffffff8c03d4e0
RBP: ffff8880297fa830 R08: ffffffff8e00c143 R09: 1ffffffff1c01828
R10: dffffc0000000000 R11: fffffbfff1c01829 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888136638c10 R15: ffff8880297f9d00
 idr_preload_end+0xed/0x200
 alloc_pid+0x79d/0xab0
 copy_process+0x1b22/0x3c20
 kernel_clone+0x21e/0x840
 __x64_sys_clone+0x185/0x1e0
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f188c78ec29
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:00007f188d619fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f188c9d5fa0 RCX: 00007f188c78ec29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f188c811e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f188c9d6038 R14: 00007f188c9d5fa0 R15: 00007ffc897c73b8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g74521 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=35934
rcu: rcu_preempt kthread starved for 10502 jiffies! g74521 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: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>
