rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8564/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=21409, q=646 ncpus=2)
task:syz.0.774       state:R  running task     stack:28264 pid:8564  tgid:8551  ppid:5838   task_flags:0x400140 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5351 [inline]
 __schedule+0x1737/0x4d30 kernel/sched/core.c:6954
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7281
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:196
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:235
Code: 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 8b 89 1c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 <e9> 0e fc b2 09 cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc9001d15f5f8 EFLAGS: 00000283
RAX: ffffffff8a2945d8 RBX: ffff888066848000 RCX: 0000000000080000
RDX: ffffc9000dc11000 RSI: 0000000000021642 RDI: 0000000000021643
RBP: ffffc9001d15f750 R08: 0000000000000000 R09: ffffffff8a2944bb
R10: dffffc0000000000 R11: fffffbfff1ea11f5 R12: ffff888066848d00
R13: ffffc9001d15fb40 R14: ffffc9001d15f660 R15: 0000000000000000
 __fib6_clean_all+0x1b8/0x380 net/ipv6/ip6_fib.c:2313
 rt6_sync_down_dev net/ipv6/route.c:5005 [inline]
 rt6_disable_ip+0x120/0x720 net/ipv6/route.c:5010
 addrconf_ifdown+0x15d/0x1880 net/ipv6/addrconf.c:3853
 addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 unregister_netdevice_many_notify+0x14d7/0x1ff0 net/core/dev.c:12156
 unregister_netdevice_many net/core/dev.c:12219 [inline]
 unregister_netdevice_queue+0x33c/0x380 net/core/dev.c:12063
 unregister_netdevice include/linux/netdevice.h:3382 [inline]
 __tun_detach+0xda4/0x1560 drivers/net/tun.c:621
 tun_detach drivers/net/tun.c:637 [inline]
 tun_chr_close+0x10a/0x1c0 drivers/net/tun.c:3433
 __fput+0x449/0xa70 fs/file_table.c:468
 fput_close_sync+0x119/0x200 fs/file_table.c:573
 __do_sys_close fs/open.c:1587 [inline]
 __se_sys_close fs/open.c:1572 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1572
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe96b58eb69
RSP: 002b:00007fe96c3fb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007fe96b7b6160 RCX: 00007fe96b58eb69
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007fe96b611df1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe96b7b6160 R15: 00007fffdfe1e828
 </TASK>