rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10499 ticks this GP) idle=bed4/1/0x4000000000000000 softirq=15264/15265 fqs=3762
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:   905093          0            0
rcu: 	cputime:    28945      23544          100   ==> 52490(ms)
rcu: 	(t=10500 jiffies g=7217 q=2758 ncpus=2)
CPU: 1 UID: 0 PID: 6255 Comm: syz.2.119 Not tainted 6.16.0-rc6-syzkaller-00411-g95993dc3039e-dirty #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:rcu_read_unlock_special+0x87/0x4c0
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 62 2c f8 10 41 f7 c6 00 00 f0 00 74 49 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001e0320 EFLAGS: 00000206
RAX: 5863f7feb07df200 RBX: 1ffff9200003c06c RCX: 5863f7feb07df200
RDX: 0000000000000002 RSI: ffffffff8d99883e RDI: ffffffff8be29f40
RBP: ffffc900001e0418 R08: ffffffff8fa1e8f7 R09: 1ffffffff1f43d1e
R10: dffffc0000000000 R11: fffffbfff1f43d1f R12: ffffffff8e144400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000002
FS:  00007f57f16a46c0(0000) GS:ffff8881a3c1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000106a6e000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __rcu_read_unlock+0x84/0xe0
 unwind_next_frame+0x19ae/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 __kfence_alloc+0x2b2/0x3b0
 kmem_cache_alloc_node_noprof+0x315/0x3c0
 kmalloc_reserve+0xbd/0x290
 __alloc_skb+0x142/0x2d0
 ndisc_alloc_skb+0x9f/0x480
 ndisc_send_rs+0x2b5/0x630
 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:preempt_schedule_irq+0xb0/0x150
Code: 24 20 f6 44 24 21 02 74 0c 90 0f 0b 48 f7 03 08 00 00 00 74 64 bf 01 00 00 00 e8 8b 1d 21 f6 e8 c6 f0 57 f6 fb bf 01 00 00 00 <e8> 1b ab ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc90007207080 EFLAGS: 00000282
RAX: 5863f7feb07df200 RBX: ffff88802169b980 RCX: 5863f7feb07df200
RDX: 0000000000000006 RSI: ffffffff8d99883e RDI: 0000000000000001
RBP: ffffc90007207130 R08: ffffffff8fa1e8f7 R09: 1ffffffff1f43d1e
R10: dffffc0000000000 R11: fffffbfff1f43d1f R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000e40e10
 irqentry_exit+0x6f/0x90
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:stack_trace_consume_entry+0x5/0x280
Code: f0 5b 41 5e 5d c3 cc cc cc cc cc e8 b5 97 c1 09 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 18 48 ba 00 00 00 00 00 fc ff
RSP: 0018:ffffc900072071f8 EFLAGS: 00000286
RAX: ffffffff81000130 RBX: ffffc900072072c0 RCX: 5863f7feb07df200
RDX: 0000000000000001 RSI: ffffffff81000130 RDI: ffffc900072072c0
RBP: ffffc90007207290 R08: ffffc90007207f48 R09: 0000000000000000
R10: ffffc90007207258 R11: ffffffff81ad0050 R12: ffff88802169b980
R13: ffff88812520c960 R14: ffffffff81ad0050 R15: ffffc90007207208
 arch_stack_walk+0x110/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 __kernfs_new_node+0xd7/0x7e0
 kernfs_new_node+0x102/0x210
 __kernfs_create_file+0x4b/0x2e0
 sysfs_add_file_mode_ns+0x238/0x300
 internal_create_group+0x66d/0x1110
 sysfs_create_groups+0x59/0x120
 device_add_attrs+0xe0/0x5a0
 device_add+0x496/0xb50
 netdev_register_kobject+0x156/0x2f0
 register_netdevice+0x126c/0x1ae0
 ppp_dev_configure+0x851/0xac0
 ppp_ioctl+0x6a5/0x19a0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f57f078e9a9
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:00007f57f16a4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f57f09b5fa0 RCX: 00007f57f078e9a9
RDX: 000000110c230000 RSI: 00000000c004743e RDI: 0000000000000007
RBP: 00007f57f0810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f57f09b5fa0 R15: 00007fff064840a8
 </TASK>
sched: DL replenish lagged too much
