rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=49837, q=310 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294987896-4294977394), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g49837 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=20907
rcu: rcu_preempt kthread starved for 10502 jiffies! g49837 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->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 stack:26664 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>
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: 13155 Comm: syz.7.2130 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:lock_release+0x29a/0x3e0
Code: c7 db a5 ba 8d e8 66 ab dd 09 b8 ff ff ff ff 65 0f c1 05 09 a9 03 11 83 f8 01 75 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 <f7> 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b
RSP: 0018:ffffc90000007818 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000087 RCX: 65dd0aa92d8def00
RDX: 0000000000000000 RSI: ffffffff8dbaa5db RDI: ffffffff8be34480
RBP: ffff888021fa4470 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f00 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88804b027a98 R15: ffff888021fa3980
FS:  00007fb7a9eb86c0(0000) GS:ffff8880b8611000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000353d6000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 _raw_spin_unlock_irqrestore+0x70/0x110
 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:lock_acquire+0x45/0x360
Code: 89 54 24 04 89 f3 49 89 fd 48 8b ac 24 98 00 00 00 65 48 8b 05 7c 7c 03 11 48 89 44 24 58 0f 1f 44 00 00 65 8b 05 7f 7c 03 11 <83> f8 08 0f 83 b8 01 00 00 89 c0 48 0f a3 05 68 41 06 0e 73 16 e8
RSP: 0018:ffffc90002be78b8 EFLAGS: 00000286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e13a160
RBP: ffffffff8172d195 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90002be7a88 R11: fffff5200057cf5d R12: 0000000000000002
R13: ffffffff8e13a160 R14: 0000000000000000 R15: 0000000000000000
 unwind_next_frame+0xc2/0x2390
 __unwind_start+0x5b9/0x760
 arch_stack_walk+0xe4/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kmem_cache_free+0x18f/0x400
 getname_flags+0x3f8/0x540
 __x64_sys_mkdirat+0x7a/0xa0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb7a8f8ec29
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:00007fb7a9eb8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fb7a91d5fa0 RCX: 00007fb7a8f8ec29
RDX: 00000000000001ff RSI: 0000000000000000 RDI: ffffffffffffff9c
RBP: 00007fb7a9011e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb7a91d6038 R14: 00007fb7a91d5fa0 R15: 00007fff48159608
 </TASK>
