rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=e2ec/1/0x4000000000000000 softirq=34771/34771 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=27741, q=315 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 9437 Comm: syz.6.780 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:do_raw_spin_lock+0x12e/0x290
Code: 00 48 89 df be 04 00 00 00 e8 5e 6e 86 00 48 8d 7c 24 40 be 04 00 00 00 e8 4f 6e 86 00 8b 44 24 40 b9 01 00 00 00 f0 0f b1 0b <0f> 85 dd 00 00 00 65 8b 1d d9 1b ae 10 48 b9 00 00 00 00 00 fc ff
RSP: 0018:ffffc900001e07c0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff888136627ac0 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900001e0800
RBP: ffffc900001e0870 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003c100 R12: ffff888136627ad0
R13: ffff888136627ac8 R14: 1ffff11026cc4f5a R15: 1ffff11026cc4f59
FS:  00007f41227df6c0(0000) GS:ffff8881a4173000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f41227bed58 CR3: 0000000116470000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 _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:nf_ct_iterate_cleanup+0xcb/0x520
Code: 89 e0 45 89 e4 25 ff 03 00 00 c1 e0 06 48 8d 80 40 6e a6 8d 48 89 44 24 10 4a 8d 04 e5 00 00 00 00 4c 89 24 24 48 89 44 24 40 <4c> 8b 2d 06 3b f3 05 49 01 c5 4d 89 ec 49 c1 ec 03 43 80 3c 34 00
RSP: 0018:ffffc90007516df0 EFLAGS: 00000202
RAX: 000000000000ce48 RBX: ffffc90007516ec0 RCX: 0000000000080000
RDX: ffffc9002475f000 RSI: 0000000000003ead RDI: 0000000000003eae
RBP: 0000000000000001 R08: ffffffff8f5cd537 R09: 1ffffffff1eb9aa6
R10: dffffc0000000000 R11: fffffbfff1eb9aa7 R12: 00000000000019c9
R13: ffff88802750ce40 R14: dffffc0000000000 R15: 1ffff92000ea2dd8
 nf_ct_netns_do_get+0x4da/0x5a0
 nf_ct_netns_get+0x44/0xb0
 nft_connlimit_do_init+0x1de/0x2e0
 nft_set_elem_expr_alloc+0x1db/0x590
 nft_set_expr_alloc+0x397/0x760
 nf_tables_newset+0x1c47/0x2530
 nfnetlink_rcv+0x1132/0x2520
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f412198ec29
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:00007f41227df038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4121bd5fa0 RCX: 00007f412198ec29
RDX: 0000000020050800 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f4121a11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4121bd6038 R14: 00007f4121bd5fa0 R15: 00007ffdd34a3208
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g27741 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=12409
rcu: rcu_preempt kthread starved for 10502 jiffies! g27741 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:27320 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
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>
