8021q: adding VLAN 0 to HW filter on device batadv0
=============================
WARNING: suspicious RCU usage
syzkaller #0 Not tainted
-----------------------------
drivers/net/ipvlan/ipvlan.h:128 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz-executor/5984:
 #0: ffffffff8f2cc248 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0
 #1: ffffffff8f39d9b0 ((inetaddr_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90

stack backtrace:
CPU: 1 UID: 0 PID: 5984 Comm: syz-executor 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
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 lockdep_rcu_suspicious+0x140/0x1d0
 ipvlan_addr_event+0x60b/0x950
 notifier_call_chain+0x1b6/0x3e0
 blocking_notifier_call_chain+0x6a/0x90
 __inet_insert_ifa+0xa13/0xbf0
 inet_rtm_newaddr+0xf3a/0x18b0
 rtnetlink_rcv_msg+0x7cf/0xb70
 netlink_rcv_skb+0x208/0x470
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f711f191503
Code: 64 89 02 48 c7 c0 ff ff ff ff eb b7 66 2e 0f 1f 84 00 00 00 00 00 90 80 3d 61 70 22 00 00 41 89 ca 74 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 55 48 83 ec 30 44 89 4c 24
RSP: 002b:00007ffc44b05f28 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f711ff14620 RCX: 00007f711f191503
RDX: 0000000000000028 RSI: 00007f711ff14670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc44b05f44 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f711ff14670 R15: 0000000000000000
 </TASK>
syz-executor (5984) used greatest stack depth: 19864 bytes left