rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=04fc/1/0x4000000000000000 softirq=19515/19515 fqs=0
rcu: 	(detected by 0, t=10505 jiffies, g=14129, q=114 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6993 Comm: syz.0.286 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 24 0e 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: ffff8880312739a8 RCX: ffff888106a48000
RDX: 0000000000010000 RSI: 0000000000000004 RDI: ffff8880312739a8
RBP: 00000000ffffffff R08: ffff888136627a83 R09: 1ffff11026cc4f50
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: ffff888031273a50
R13: dffffc0000000000 R14: ffff8880312739a8 R15: ffffffffffff4028
FS:  00007fa119a9a6c0(0000) GS:ffff8881a3c12000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3261fff8 CR3: 0000000111fac000 CR4: 00000000000006f0
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:do_syscall_64+0xc3/0x3b0
Code: 00 48 8b 7d 08 48 89 7b 18 e8 09 5a 00 00 0f 1f 44 00 00 0f 1f 44 00 00 90 e8 39 fb 4c f6 90 90 e8 e2 fa 4c f6 fb 49 8b 57 08 <f6> c2 3f 74 0e 4c 89 f7 4c 89 ee e8 fd ed 2f f6 49 89 c4 90 90 41
RSP: 0018:ffffc900084f7ef0 EFLAGS: 00000286
RAX: 2e2f5869fe402700 RBX: ffffc900084f7ef0 RCX: 2e2f5869fe402700
RDX: 0000000000000000 RSI: ffffffff8d9baa25 RDI: ffffffff8be34280
RBP: ffffc900084f7f48 R08: ffffffff8fa3b237 R09: 1ffffffff1f47646
R10: dffffc0000000000 R11: fffffbfff1f47647 R12: 0000000000000035
R13: 0000000000000035 R14: ffffc900084f7f58 R15: ffff888106a48000
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa118b8ec29
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:00007fa119a9a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007fa118dd5fa0 RCX: 00007fa118b8ec29
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 00007fa118c11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000180 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa118dd6038 R14: 00007fa118dd5fa0 R15: 00007ffc1d5574a8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g14129 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=5798
rcu: rcu_preempt kthread starved for 10505 jiffies! g14129 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>
