rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=a1c4/1/0x4000000000000000 softirq=40687/40687 fqs=0
rcu: 	(detected by 1, t=10506 jiffies, g=35021, q=392 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10960 Comm: syz.5.1552 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+0x6ba/0xd20
Code: a9 00 00 18 00 0f 84 b3 00 00 00 4c 89 f6 ba 08 00 00 00 e8 88 25 00 00 45 31 ff 85 c0 0f 84 f5 05 00 00 83 3d 36 b9 0e 18 00 <75> 13 48 63 44 24 20 48 0f a3 05 a7 29 0b 12 0f 83 15 05 00 00 31
RSP: 0018:ffffc90000007750 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000002 RCX: ffffffff9349f388
RDX: 0000000000000008 RSI: ffff888106a48af0 RDI: ffff888106a48000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81ada78b
R10: dffffc0000000000 R11: ffffed1009604f51 R12: ffffffffffffff02
R13: 0000000000000002 R14: ffff888106a48af0 R15: 0000000000000000
FS:  00007f75b80bd6c0(0000) GS:ffff8880b8612000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f75b807afc8 CR3: 000000003dc62000 CR4: 00000000000006f0
DR0: 0000200000000300 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:send_sig_perf+0xf6/0x1c0
Code: 65 4c 8b 34 25 08 e0 a0 92 49 8d be 30 09 00 00 48 89 f8 48 c1 e8 03 42 80 3c 38 00 74 05 e8 41 8c 9c 00 41 8b 86 30 09 00 00 <c1> e8 04 83 e0 01 89 44 24 64 48 c7 44 24 18 00 00 00 00 48 8d 74
RSP: 0018:ffffc90001d9fcc0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90001d9fd00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888106a48930
RBP: ffffc90001d9fdb0 R08: ffffc90001d9fd2f R09: 0000000000000000
R10: ffffc90001d9fd00 R11: fffff520003b3fa6 R12: 0000000000000000
R13: 1ffff920003b3f9c R14: ffff888106a48000 R15: dffffc0000000000
 perf_pending_task+0x203/0x3f0
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f75b718ec29
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:00007f75b80bd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 00007f75b73d5fa8 RCX: 00007f75b718ec29
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f75b73d5fa8
RBP: 00007f75b73d5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75b73d6038 R14: 00007fffd3dd3f20 R15: 00007fffd3dd4008
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g35021 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=16335
rcu: rcu_preempt kthread starved for 10506 jiffies! g35021 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26664 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>
