syzbot

==================================================================
BUG: KCSAN: data-race in l3mdev_master_ifindex_rcu / macvlan_common_newlink

read to 0xffff88813705e0c8 of 8 bytes by task 22705 on cpu 1:
 netif_is_l3_master include/linux/netdevice.h:5047 [inline]
 l3mdev_master_ifindex_rcu+0x22/0xc0 net/l3mdev/l3mdev.c:117
 ipv6_dev_get_saddr+0x1aa/0x430 net/ipv6/addrconf.c:1835
 ip6_route_get_saddr include/net/ip6_route.h:141 [inline]
 ip6_dst_lookup_tail+0x2f1/0x930 net/ipv6/ip6_output.c:1115
 ip6_dst_lookup_flow+0x48/0xc0 net/ipv6/ip6_output.c:1240
 geneve_get_v6_dst+0x315/0x5f0 drivers/net/geneve.c:881
 geneve6_xmit_skb drivers/net/geneve.c:1016 [inline]
 geneve_xmit+0x6ea/0x2300 drivers/net/geneve.c:1100
 __netdev_start_xmit include/linux/netdevice.h:4889 [inline]
 netdev_start_xmit include/linux/netdevice.h:4903 [inline]
 xmit_one net/core/dev.c:3573 [inline]
 dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3589
 __dev_queue_xmit+0xf27/0x1e20 net/core/dev.c:4369
 dev_queue_xmit include/linux/netdevice.h:3082 [inline]
 neigh_hh_output include/net/neighbour.h:526 [inline]
 neigh_output include/net/neighbour.h:540 [inline]
 ip6_finish_output2+0x994/0xc50 net/ipv6/ip6_output.c:135
 __ip6_finish_output net/ipv6/ip6_output.c:196 [inline]
 ip6_finish_output+0x3a0/0x4f0 net/ipv6/ip6_output.c:207
 NF_HOOK_COND include/linux/netfilter.h:293 [inline]
 ip6_output+0xeb/0x220 net/ipv6/ip6_output.c:228
 dst_output include/net/dst.h:458 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 mld_sendpack+0x438/0x6a0 net/ipv6/mcast.c:1818
 mld_send_cr net/ipv6/mcast.c:2119 [inline]
 mld_ifc_work+0x519/0x7b0 net/ipv6/mcast.c:2651
 process_one_work kernel/workqueue.c:2630 [inline]
 process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
 worker_thread+0x525/0x730 kernel/workqueue.c:2784
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

read-write to 0xffff88813705e0c8 of 8 bytes by task 17929 on cpu 0:
 macvlan_port_create drivers/net/macvlan.c:1275 [inline]
 macvlan_common_newlink+0x932/0xbc0 drivers/net/macvlan.c:1489
 macvlan_newlink+0x35/0x40 drivers/net/macvlan.c:1581
 rtnl_newlink_create net/core/rtnetlink.c:3485 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3705 [inline]
 rtnl_newlink+0xee5/0x1670 net/core/rtnetlink.c:3718
 rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6442
 netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6460
 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
 netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368
 netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2558
 ___sys_sendmsg net/socket.c:2612 [inline]
 __sys_sendmsg+0x1e9/0x270 net/socket.c:2641
 __do_sys_sendmsg net/socket.c:2650 [inline]
 __se_sys_sendmsg net/socket.c:2648 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2648
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17929 Comm: syz-executor.4 Not tainted 6.6.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
==================================================================