syzbot

IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
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BUG: KCSAN: data-race in fib6_ifup / find_match

read to 0xffff888095dc80af of 1 bytes by interrupt on cpu 1:
 find_match+0x52/0x7f0 net/ipv6/route.c:744
 __find_rr_leaf+0xe3/0x780 net/ipv6/route.c:835
 find_rr_leaf net/ipv6/route.c:856 [inline]
 rt6_select net/ipv6/route.c:900 [inline]
 fib6_table_lookup+0x383/0x650 net/ipv6/route.c:2168
 ip6_pol_route+0xee/0x730 net/ipv6/route.c:2204
 ip6_pol_route_input+0x4d/0x70 net/ipv6/route.c:2262
 fib6_rule_lookup+0x95/0x470 net/ipv6/fib6_rules.c:114
 ip6_route_input_lookup+0x9f/0xc0 net/ipv6/route.c:2274
 ip6_route_input+0x41e/0x4b0 net/ipv6/route.c:2443
 ip6_rcv_finish_core.isra.0+0x97/0x1f0 net/ipv6/ip6_input.c:63
 ip6_rcv_finish+0xee/0x140 net/ipv6/ip6_input.c:74
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ipv6_rcv+0x1a1/0x1b0 net/ipv6/ip6_input.c:306
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5150
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5264
 process_backlog+0x207/0x4b0 net/core/dev.c:6095
 napi_poll net/core/dev.c:6532 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6600
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 run_ksoftirqd+0x46/0x60 kernel/softirq.c:603
 smpboot_thread_fn+0x37d/0x4a0 kernel/smpboot.c:165
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

write to 0xffff888095dc80af of 1 bytes by task 17032 on cpu 0:
 fib6_ifup+0xd7/0x100 net/ipv6/route.c:4592
 fib6_clean_node+0x194/0x310 net/ipv6/ip6_fib.c:2099
 fib6_walk_continue+0x2e3/0x440 net/ipv6/ip6_fib.c:2024
 fib6_walk+0x10d/0x160 net/ipv6/ip6_fib.c:2072
 fib6_clean_tree+0xef/0x120 net/ipv6/ip6_fib.c:2152
 __fib6_clean_all+0xbd/0x150 net/ipv6/ip6_fib.c:2168
 fib6_clean_all+0x34/0x50 net/ipv6/ip6_fib.c:2179
 rt6_sync_up+0x9f/0x110 net/ipv6/route.c:4612
 addrconf_notify+0x1158/0x1550 net/ipv6/addrconf.c:3567
 notifier_call_chain+0xd7/0x160 kernel/notifier.c:83
 __raw_notifier_call_chain kernel/notifier.c:361 [inline]
 raw_notifier_call_chain+0x37/0x50 kernel/notifier.c:368
 call_netdevice_notifiers_info net/core/dev.c:1893 [inline]
 call_netdevice_notifiers_info+0x9a/0x120 net/core/dev.c:1878
 netdev_state_change net/core/dev.c:1378 [inline]
 netdev_state_change+0xb2/0xd0 net/core/dev.c:1371
 do_setlink+0xdf2/0x1ee0 net/core/rtnetlink.c:2809
 rtnl_group_changelink net/core/rtnetlink.c:3089 [inline]
 __rtnl_newlink+0xa86/0x1090 net/core/rtnetlink.c:3243
 rtnl_newlink+0x63/0x90 net/core/rtnetlink.c:3363
 rtnetlink_rcv_msg+0x1d3/0x500 net/core/rtnetlink.c:5424
 netlink_rcv_skb+0xb0/0x260 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x26/0x30 net/core/rtnetlink.c:5442
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x3a6/0x4d0 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x4d3/0x8b0 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 ____sys_sendmsg+0x49d/0x4d0 net/socket.c:2330
 ___sys_sendmsg+0xb5/0x100 net/socket.c:2384
 __sys_sendmsg+0xa0/0x160 net/socket.c:2417
 __do_sys_sendmsg net/socket.c:2426 [inline]
 __se_sys_sendmsg net/socket.c:2424 [inline]
 __x64_sys_sendmsg+0x51/0x70 net/socket.c:2424
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17032 Comm: syz-executor.3 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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