rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (8680 ticks this GP) idle=1b0c/1/0x4000000000000000 softirq=23664/23676 fqs=5188
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:   955367          0            0
rcu: 	cputime:    24098      28390          100   ==> 52490(ms)
rcu: 	(t=10501 jiffies g=16869 q=2331 ncpus=2)
CPU: 0 UID: 0 PID: 8021 Comm: syz.2.596 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:unwind_next_frame+0x374/0x2390
Code: ea 48 01 d2 48 01 f2 48 bd 00 00 00 00 00 fc ff df 0f 84 37 01 00 00 4c 8d 62 04 4c 8d 6a 05 4c 89 e0 48 c1 e8 03 0f b6 04 28 <84> c0 0f 85 6d 19 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f
RSP: 0018:ffffc90000006ff8 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffffffff90276cb4 RCX: ffffffff90276cbc
RDX: ffffffff90db6cba RSI: ffffffff90db6c8a RDI: ffffffff8be332a0
RBP: dffffc0000000000 R08: 000000000000000c R09: ffffffff8172c195
R10: ffffc90000007118 R11: ffffffff81ac3930 R12: ffffffff90db6cbe
R13: ffffffff90db6cbf R14: ffffc900000070c8 R15: ffffffff90276cb8
FS:  00007f888cc756c0(0000) GS:ffff8880b861c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa94b48b440 CR3: 000000003aeea000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 __kfence_alloc+0x2b2/0x3b0
 __kmalloc_cache_noprof+0x329/0x3d0
 ref_tracker_alloc+0x133/0x460
 ___neigh_create+0xc9e/0x2260
 ip6_finish_output2+0xb4d/0x16a0
 ndisc_send_skb+0xb54/0x1440
 addrconf_rs_timer+0x369/0x670
 call_timer_fn+0x17e/0x5f0
 __run_timer_base+0x61a/0x860
 run_timer_softirq+0xb7/0x180
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_irq_work+0xa3/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x1a/0x20
RIP: 0010:lock_acquire+0x175/0x360
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 4b e3 02 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90002daf798 EFLAGS: 00000206
RAX: c2381203d2d63100 RBX: 0000000000000000 RCX: c2381203d2d63100
RDX: 0000000000000000 RSI: ffffffff8dba5cac RDI: ffffffff8be33300
RBP: ffffffff825c06c6 R08: 0000000000000000 R09: ffffffff825c06c6
R10: dffffc0000000000 R11: ffffed1004970617 R12: 0000000000000000
R13: ffffffff8e2c3b38 R14: 0000000000000001 R15: 0000000000000246
 _raw_spin_lock+0x2e/0x40
 __register_sysctl_table+0xef6/0x1340
 __addrconf_sysctl_register+0x328/0x4c0
 addrconf_sysctl_register+0x168/0x1c0
 ipv6_add_dev+0xd46/0x1370
 addrconf_notify+0x794/0x1010
 notifier_call_chain+0x1b6/0x3e0
 register_netdevice+0x1608/0x1ae0
 ppp_dev_configure+0x8a4/0xb10
 ppp_ioctl+0x6a5/0x19a0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f888bd8ebe9
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:00007f888cc75038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f888bfb5fa0 RCX: 00007f888bd8ebe9
RDX: 000000110c230007 RSI: 00000000c004743e RDI: 0000000000000009
RBP: 00007f888be11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f888bfb6038 R14: 00007f888bfb5fa0 R15: 00007ffef3afef68
 </TASK>
sched: DL replenish lagged too much
