rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10500 ticks this GP) idle=f0fc/1/0x4000000000000000 softirq=101907/101907 fqs=259
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:     5842          1            0
rcu: 	cputime:      168      52183           19   ==> 52370(ms)
rcu: 	(t=10502 jiffies g=104689 q=4473 ncpus=2)
CPU: 1 UID: 0 PID: 28182 Comm: syz.1.6147 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:cake_dequeue+0xa33/0x4f40
Code: 0f 85 cc 01 00 00 4c 8b 6c 24 38 45 0f b7 bd 82 98 01 00 43 0f b6 04 26 84 c0 0f 85 cb 01 00 00 44 01 fd 41 89 ad 84 98 01 00 <4d> 89 ec 48 8d 7b 02 48 89 f8 48 c1 e8 03 49 bf 00 00 00 00 00 fc
RSP: 0018:ffffc90000a07e60 EFLAGS: 00000286
RAX: 0000000000000000 RBX: ffff88802321982c RCX: ffff8881780a1d80
RDX: 0000000000000100 RSI: 00000000e6106c4d RDI: ffff888023219882
RBP: 00000000e610704d R08: ffffffff9030b1f7 R09: 1ffffffff206163e
R10: dffffc0000000000 R11: ffffffff817652a0 R12: dffffc0000000000
R13: ffff888023200000 R14: 1ffff11004643310 R15: 0000000000000400
FS:  00007f27e8ffa6c0(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000d6000 CR3: 00000001a5a6a000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __qdisc_run+0x23f/0x1560
 __dev_queue_xmit+0x1d26/0x3950
 ip6_output+0x340/0x550
 ip6_send_skb+0x1d5/0x390
 icmp6_send+0x143b/0x1b50
 udpv6_rcv+0x12a8/0x1bd0
 ip6_protocol_deliver_rcu+0xdf8/0x1740
 ip6_input_finish+0x191/0x370
 NF_HOOK+0x336/0x3c0
 ip6_input+0x16a/0x270
 NF_HOOK+0x336/0x3c0
 process_backlog+0x7dd/0x1950
 __napi_poll+0xae/0x340
 net_rx_action+0x627/0xf70
 handle_softirqs+0x22a/0x840
 do_softirq+0x76/0xd0
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130
 __dev_queue_xmit+0x1fe5/0x3950
 __neigh_update+0x9df/0x27b0
 arp_req_set+0x442/0x890
 arp_ioctl+0x384/0x490
 inet_ioctl+0x3c4/0x560
 sock_do_ioctl+0x101/0x320
 sock_ioctl+0x5c6/0x7f0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f27e819cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f27e8ffa028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f27e8416180 RCX: 00007f27e819cdd9
RDX: 00002000000005c0 RSI: 0000000000008955 RDI: 000000000000000f
RBP: 00007f27e8232d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f27e8416218 R14: 00007f27e8416180 R15: 00007ffd69825108
 </TASK>
sched: DL replenish lagged too much
