rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=3244/1/0x4000000000000000 softirq=33017/33017 fqs=0
rcu: 	(detected by 1, t=10502 jiffies, g=25053, q=193 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9517 Comm: syz.3.1007 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:preempt_count_sub+0x27/0x170
Code: 90 90 90 f3 0f 1e fa 55 53 48 bb 00 00 00 00 00 fc ff df 48 c7 c0 20 43 ac 99 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 d1 00 00 00 <83> 3d 12 2f 1c 18 00 75 25 65 8b 05 19 dc 10 11 89 c1 81 e1 ff ff
RSP: 0018:ffffc90000007868 EFLAGS: 00000097
RAX: 0000000000000004 RBX: dffffc0000000000 RCX: ffffffff99ac4303
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000001
RBP: ffffc90000007918 R08: ffff88804b027a83 R09: 1ffff11009604f50
R10: dffffc0000000000 R11: ffffed1009604f51 R12: dffffc0000000000
R13: ffff88804b027b00 R14: ffff88804b027a80 R15: 1ffff92000000f10
FS:  00007f09b18fa6c0(0000) GS:ffff8880b8611000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000027128000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 _raw_spin_unlock_irqrestore+0xad/0x110
 hrtimer_try_to_cancel+0x3be/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:__sanitizer_cov_trace_const_cmp8+0x37/0x90
Code: 08 f0 a0 92 65 8b 15 98 25 e1 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 83 b9 3c 16 00 00 00 74 4e 8b 91 18 16 00 00 <83> fa 03 75 43 48 8b 91 20 16 00 00 44 8b 89 1c 16 00 00 49 c1 e1
RSP: 0018:ffffc9000637fe08 EFLAGS: 00000246
RAX: ffffffff817495dd RBX: ffff88811f19a200 RCX: ffff8881076e8000
RDX: 0000000000000002 RSI: ffff88811f19a200 RDI: ffffffff7fffffff
RBP: 1ffff11020edd130 R08: ffff88811f19b1ff R09: 1ffff11023e3363f
R10: dffffc0000000000 R11: ffffed1023e33640 R12: fffffffffffffff2
R13: ffffea0000000000 R14: ffff888100014640 R15: dffffc0000000000
 __phys_addr+0x2d/0x180
 kmem_cache_free+0x7e/0x400
 getname_flags+0x3f8/0x540
 __x64_sys_mkdirat+0x7a/0xa0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f09b098ec29
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:00007f09b18fa038 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f09b0bd5fa0 RCX: 00007f09b098ec29
RDX: 00000000000001ff RSI: 0000000000000000 RDI: ffffffffffffff9c
RBP: 00007f09b0a11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f09b0bd6038 R14: 00007f09b0bd5fa0 R15: 00007ffc71c2d7c8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g25053 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=11908
rcu: rcu_preempt kthread starved for 10502 jiffies! g25053 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:26920 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>
