rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=6444/1/0x4000000000000000 softirq=34602/34602 fqs=0
rcu: 	(detected by 0, t=10506 jiffies, g=27225, q=220 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 11339 Comm: syz.1.1458 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:hrtimer_cancel+0x33/0x50
Code: e8 42 15 12 00 48 89 df e8 9a f9 ff ff 89 c5 31 ff 89 c6 e8 6f 19 12 00 85 ed 78 0c e8 26 15 12 00 eb 1a e8 1f 15 12 00 f3 90 <48> 89 df e8 75 f9 ff ff 85 c0 78 ed 89 c5 e8 0a 15 12 00 89 e8 5b
RSP: 0018:ffffc900001e0990 EFLAGS: 00000006
RAX: ffffffff81adabe1 RBX: ffff88803c8db9a8 RCX: ffff88801ef58000
RDX: 0000000000010000 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: 00000000ffffffff R08: ffff888136627a83 R09: 1ffff11026cc4f50
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: ffff88803c8dba50
R13: dffffc0000000000 R14: ffff88803c8db9a8 R15: ffffffffffff5446
FS:  00007fe81c7496c0(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe81c748fc8 CR3: 000000011c060000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 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:do_syscall_64+0xfe/0x3b0
Code: 89 c4 90 90 41 81 fc d5 01 00 00 0f 87 81 01 00 00 41 81 fc d6 01 00 00 48 19 f6 44 21 e6 4c 89 f7 e8 96 6f b9 f5 49 89 46 50 <90> 90 4d 8b 67 08 4c 89 f7 e8 94 91 b9 f5 0f 1f 44 00 00 48 c7 43
RSP: 0018:ffffc90003b4fef0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffc90003b4fef0 RCX: f99b38dc73ef2d00
RDX: ffffc9002935b000 RSI: 0000000000000007 RDI: 0000000000000008
RBP: ffffc90003b4ff48 R08: 0000000000000000 R09: ffffffff81b2e6db
R10: dffffc0000000000 R11: ffffed102111d006 R12: 00000000000000ca
R13: 00000000000000ca R14: ffffc90003b4ff58 R15: ffff88801ef58000
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe81b98eba9
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:00007fe81c7490e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007fe81bbd5fa8 RCX: 00007fe81b98eba9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fe81bbd5fac
RBP: 00007fe81bbd5fa0 R08: 7fffffffffffffff R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe81bbd6038 R14: 00007ffd73459f20 R15: 00007ffd7345a008
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g27225 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=20781
rcu: rcu_preempt kthread starved for 10506 jiffies! g27225 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:26632 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>
