syzbot

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BUG: KCSAN: data-race in ip6_sk_dst_lookup_flow / ip6_sk_dst_store_flow

write to 0xffff88813a2e3538 of 4 bytes by task 27237 on cpu 0:
 ip6_dst_store include/net/ip6_route.h:234 [inline]
 ip6_sk_dst_store_flow+0x181/0x1b0 net/ipv6/route.c:2980
 ip6_datagram_dst_update+0x451/0x4a0 net/ipv6/datagram.c:107
 __ip6_datagram_connect+0x753/0x860 net/ipv6/datagram.c:248
 ip6_datagram_connect+0x2a/0x40 net/ipv6/datagram.c:272
 inet_dgram_connect+0x107/0x190 net/ipv4/af_inet.c:576
 __sys_connect_file net/socket.c:1896 [inline]
 __sys_connect+0x197/0x1b0 net/socket.c:1913
 __do_sys_connect net/socket.c:1923 [inline]
 __se_sys_connect net/socket.c:1920 [inline]
 __x64_sys_connect+0x3d/0x50 net/socket.c:1920
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813a2e3538 of 4 bytes by task 27238 on cpu 1:
 ip6_sk_dst_lookup_flow+0x8b/0x4a0 net/ipv6/ip6_output.c:1232
 udpv6_sendmsg+0x13f9/0x16e0 net/ipv6/udp.c:1522
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:644
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 __sys_sendto+0x21e/0x2c0 net/socket.c:2036
 __do_sys_sendto net/socket.c:2048 [inline]
 __se_sys_sendto net/socket.c:2044 [inline]
 __x64_sys_sendto+0x74/0x90 net/socket.c:2044
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x0000002d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27238 Comm: syz-executor.0 Tainted: G        W         5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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