IPv6: NLM_F_CREATE should be specified when creating new route
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:578
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 4383, name: syz.2.16
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
1 lock held by syz.2.16/4383:
 #0: ffffffff841f37f0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff841f37f0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff841f37f0 (rcu_read_lock){....}-{1:2}, at: ip6_route_add+0x39/0x120 net/ipv6/route.c:3906
CPU: 1 UID: 0 PID: 4383 Comm: syz.2.16 Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xa2/0xf0 lib/dump_stack.c:120
 __might_resched+0x1bc/0x1e0 kernel/sched/core.c:8818
 __mutex_lock_common kernel/locking/mutex.c:578 [inline]
 __mutex_lock+0x7c/0xba0 kernel/locking/mutex.c:746
 pcpu_alloc_noprof+0x198/0xa10 mm/percpu.c:1782
 dst_cache_init+0x25/0x50 net/core/dst_cache.c:145
 ip_tun_build_state+0x108/0x230 net/ipv4/ip_tunnel_core.c:687
 lwtunnel_build_state+0xe7/0x150 net/core/lwtunnel.c:137
 fib_nh_common_init+0x8e/0x190 net/ipv4/fib_semantics.c:635
 fib6_nh_init+0x8e8/0xe30 net/ipv6/route.c:3662
 ip6_route_info_create_nh+0xf1/0x2a0 net/ipv6/route.c:3859
 ip6_route_add+0x67/0x120 net/ipv6/route.c:3908
 inet6_rtm_newroute+0xcc/0x870 net/ipv6/route.c:5712
 rtnetlink_rcv_msg+0x36c/0x3b0 net/core/rtnetlink.c:6955
 netlink_rcv_skb+0xe4/0x110 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x1d9/0x2f0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x30c/0x3d0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x81/0xa0 net/socket.c:727
 ____sys_sendmsg+0x1aa/0x230 net/socket.c:2566
 ___sys_sendmsg+0x289/0x2d0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0xe9/0x140 net/socket.c:2655
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x8f/0x170 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f14b998e969
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:00007f14ba7e8038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f14b9bb5fa0 RCX: 00007f14b998e969
RDX: 000000001000c840 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007f14b9a10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f14b9bb5fa0 R15: 00007fff6b822ab8
 </TASK>
IPv6: Can't replace route, no match found