=============================
WARNING: suspicious RCU usage
5.16.0-rc8-syzkaller #0 Not tainted
-----------------------------
include/linux/netfilter_netdev.h:97 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syz-executor.2/4620:
 #0: ffff88802afcb1e0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1645 [inline]
 #0: ffff88802afcb1e0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: rawv6_sendmsg+0x1490/0x3a20 net/ipv6/raw.c:948
 #1: ffffffff8bb81240 (rcu_read_lock_bh){....}-{1:2}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline]
 #1: ffffffff8bb81240 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x2ad/0x14e0 net/ipv6/ip6_output.c:112
 #2: ffffffff8bb81240 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1e3/0x3650 net/core/dev.c:4153

stack backtrace:
CPU: 1 PID: 4620 Comm: syz-executor.2 Not tainted 5.16.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nf_hook_egress include/linux/netfilter_netdev.h:97 [inline]
 __dev_queue_xmit+0x2ec3/0x3650 net/core/dev.c:4170
 neigh_connected_output+0x3b6/0x510 net/core/neighbour.c:1551
 neigh_output include/net/neighbour.h:527 [inline]
 ip6_finish_output2+0x571/0x14e0 net/ipv6/ip6_output.c:126
 ip6_fragment+0xa8f/0x2700 net/ipv6/ip6_output.c:966
 __ip6_finish_output net/ipv6/ip6_output.c:189 [inline]
 __ip6_finish_output+0x5fa/0x1050 net/ipv6/ip6_output.c:170
 ip6_finish_output+0x32/0x200 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x1e4/0x530 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:450 [inline]
 ip6_local_out+0xaf/0x1a0 net/ipv6/output_core.c:161
 ip6_send_skb+0xb7/0x340 net/ipv6/ip6_output.c:1912
 ip6_push_pending_frames+0xdd/0x100 net/ipv6/ip6_output.c:1932
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x2b0c/0x3a20 net/ipv6/raw.c:956
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7ffb0dc71e99
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffb0c5e7168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffb0dd84f60 RCX: 00007ffb0dc71e99
RDX: 0000000000000004 RSI: 0000000020000a40 RDI: 0000000000000005
RBP: 00007ffb0dccbff1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffc3f7a78f R14: 00007ffb0c5e7300 R15: 0000000000022000
 </TASK>