rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=93197, q=521 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10492 (4295011442-4295000950), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10491 jiffies! g93197 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=35755
rcu: rcu_preempt kthread starved for 10492 jiffies! g93197 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->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 stack:26216 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 20757 Comm: syz.4.4098 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:__sanitizer_cov_trace_pc+0x0/0x70
Code: 89 fb e8 23 00 00 00 48 8b 3d e4 ff 1b 0c 48 89 de 5b e9 43 13 5a 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 d0 c1 92 65 8b 15 e8 79
RSP: 0018:ffffc90000007678 EFLAGS: 00000003
RAX: 1ffffffff1c4181d RBX: 000000000000002c RCX: ffffe8ff1462f098
RDX: ffffc90000007740 RSI: ffffc90000007720 RDI: 000000000000002c
RBP: ffffc900000077c0 R08: 0000000000000000 R09: 0000000000000001
R10: dffffc0000000000 R11: ffffed1009604f59 R12: 1ffff92000000ee0
R13: 0000000000000012 R14: ffffc90000007720 R15: ffffc90000007740
FS:  00007f1de4f976c0(0000) GS:ffff8880b8403000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000f000 CR3: 00000000405d8000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 perf_trace_buf_alloc+0x1c/0x2a0
 perf_trace_lock_acquire+0x196/0x410
 lock_acquire+0x311/0x360
 _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+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 4a 26 1d f6 48 89 df e8 a2 bd 1d f6 e8 7d 19 47 f6 fb bf 01 00 00 00 <e8> 82 b4 0f f6 65 8b 05 3b e8 40 07 85 c0 74 07 5b c3 cc cc cc cc
RSP: 0018:ffffc90004057b98 EFLAGS: 00000282
RAX: 3c4ab7adfc8a9b00 RBX: ffff888037ad3400 RCX: 3c4ab7adfc8a9b00
RDX: 0000000000000006 RSI: ffffffff8db9e917 RDI: 0000000000000001
RBP: 0000000000000001 R08: ffffffff8fc34377 R09: 1ffffffff1f8686e
R10: dffffc0000000000 R11: fffffbfff1f8686f R12: ffff88810724f128
R13: dffffc0000000000 R14: ffff888037ad3400 R15: 1ffff11020e49e25
 _perf_event_refresh+0x107/0x250
 perf_ioctl+0x5e5/0x1ec0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1de418ec29
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:00007f1de4f97038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1de43d5fa0 RCX: 00007f1de418ec29
RDX: 0000000000000001 RSI: 0000000000002402 RDI: 0000000000000008
RBP: 00007f1de4211e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1de43d6038 R14: 00007f1de43d5fa0 R15: 00007ffd1f4bd848
 </TASK>
