rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=dc1c/1/0x4000000000000000 softirq=19515/19515 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=12417, q=167 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7122 Comm: syz.3.350 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_try_to_cancel+0x0/0x420
Code: ef e8 d4 10 76 00 e9 c4 fe ff ff 66 66 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 83 ec 30 48 89 fb 49
RSP: 0018:ffffc900001e0988 EFLAGS: 00000006
RAX: ffffffff81adabe1 RBX: ffff888030189428 RCX: ffff888106143980
RDX: 0000000000010000 RSI: 0000000000000004 RDI: ffff888030189428
RBP: 00000000ffffffff R08: ffff888136627a83 R09: 1ffff11026cc4f50
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: ffff8880301894d0
R13: dffffc0000000000 R14: ffff888030189428 R15: fffffffffffefbd5
FS:  00007f3a858fc6c0(0000) GS:ffff8881a3c12000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000011338e000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 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:_raw_spin_lock_irq+0x0/0xf0
Code: 8d 65 e0 5b 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc e8 b4 6a fd ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 41 57 41 56 53 48 83 e4 e0 48 83 ec 60 48
RSP: 0018:ffffc900035bfc88 EFLAGS: 00000a02
RAX: ffff88810822c318 RBX: ffff888106061ca0 RCX: 1ffff11020c287e2
RDX: 1ffff11020c2885b RSI: ffffffff8dbaa21a RDI: ffff88810822c280
RBP: ffff888106143f00 R08: ffff888106143987 R09: 1ffff11020c28730
R10: dffffc0000000000 R11: ffffed1020c28731 R12: ffff8881061442c8
R13: 1ffff11020c0c395 R14: ffff888106061cac R15: ffff888106143980
 get_signal+0x23a/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3a8498ec29
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:00007f3a858fc0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f3a84bd5fa8 RCX: 00007f3a8498ec29
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3a84bd5fa8
RBP: 00007f3a84bd5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3a84bd6038 R14: 00007ffdaf9264a0 R15: 00007ffdaf926588
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g12417 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=5588
rcu: rcu_preempt kthread starved for 10502 jiffies! g12417 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:27160 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>
