rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=17081, q=256 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10497 (4294960239-4294949742), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10497 jiffies! g17081 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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  running task     stack:27288 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+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: 8317 Comm: syz.0.734 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:its_return_thunk+0x0/0x10
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <c3> cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 2b 9a ac f5 cc
RSP: 0018:ffffc900000077b8 EFLAGS: 00000056
RAX: 00000000ffffff01 RBX: ffff88804b027ac0 RCX: ffffffff819e1452
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff88804b027ac0
RBP: ffffc90000007870 R08: ffff88804b027ac3 R09: 1ffff11009604f58
R10: dffffc0000000000 R11: ffffed1009604f59 R12: ffff88804b027ad0
R13: ffff88804b027ac8 R14: 1ffff11009604f5a R15: 1ffff11009604f59
FS:  00007efd3d0326c0(0000) GS:ffff8880b83e0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000003 CR3: 0000000122eda000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 do_raw_spin_lock+0x112/0x290
 _raw_spin_lock_irqsave+0xb3/0xf0
 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:perf_ioctl+0xd96/0x1ec0
Code: db 4d 85 e4 0f 95 c3 49 83 c6 20 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 aa 10 00 00 41 89 1e e8 8d 9c fb ff 45 31 ff <48> 8b 9c 24 90 00 00 00 48 89 df 48 83 c7 40 e8 b6 cd 92 09 48 89
RSP: 0018:ffffc90009e7fbe0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff8dbc0fba RDI: 00000000ffffffff
RBP: ffffc90009e7fe98 R08: ffffffff8fc43c37 R09: 1ffffffff1f88786
R10: dffffc0000000000 R11: fffffbfff1f88787 R12: 0000000000000003
R13: dffffc0000000000 R14: ffff8880297f6400 R15: 0000000000000000
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efd3c18eba9
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:00007efd3d032038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007efd3c3d6270 RCX: 00007efd3c18eba9
RDX: 0000000000000003 RSI: 0000000000002402 RDI: 0000000000000009
RBP: 00007efd3c211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efd3c3d6308 R14: 00007efd3c3d6270 R15: 00007ffe5a581b28
 </TASK>
