rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=4f0c/1/0x4000000000000000 softirq=20639/20639 fqs=0
rcu: 	(detected by 0, t=10505 jiffies, g=16425, q=296 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7585 Comm: syz.1.466 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+0xee/0x360
Code: 00 00 00 00 9c 8f 44 24 30 4c 89 74 24 10 4d 89 fe 4c 8b 7c 24 30 fa 48 c7 c7 c8 ea 9c 8d e8 29 be dd 09 65 ff 05 d2 bb 03 11 <45> 31 c9 4c 89 7c 24 08 41 f7 c7 00 02 00 00 41 0f 94 c1 4c 89 ef
RSP: 0018:ffffc900001e07e0 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 318c3cbbfcbaa400
RDX: 0000000000000000 RSI: ffffffff8d9ceac8 RDI: ffffffff8be34480
RBP: ffffffff81adabcb R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: 0000000000000000
R13: ffff888136627a98 R14: 0000000000000001 R15: 0000000000000046
FS:  00007f79f91b36c0(0000) GS:ffff8881a3c11000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f79f9170fc8 CR3: 000000012dffe000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 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+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:__x64_sys_perf_event_open+0x0/0xc0
Code: 48 89 ef e8 52 82 33 00 e9 9e fd ff ff 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 89 fb 48 bd 00 00 00
RSP: 0018:ffffc90006bb7ee8 EFLAGS: 00000246
RAX: 318c3cbbfcbaa400 RBX: ffffc90006bb7ef0 RCX: 318c3cbbfcbaa400
RDX: 0000000000000000 RSI: 000000000000012a RDI: ffffc90006bb7f58
RBP: ffffc90006bb7f48 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: 000000000000012a
R13: 000000000000012a R14: ffffc90006bb7f58 R15: ffff8881071a1cc0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f79f838ec29
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:00007f79f91b3038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f79f85d5fa0 RCX: 00007f79f838ec29
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000200000000000
RBP: 00007f79f8411e41 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f79f85d6038 R14: 00007f79f85d5fa0 R15: 00007ffc4d1be978
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g16425 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=5970
rcu: rcu_preempt kthread starved for 10505 jiffies! g16425 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:26792 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>
