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BUG: KCSAN: data-race in pcpu_alloc / pcpu_chunk_populated

write to 0xffffffff86253180 of 4 bytes by task 8092 on cpu 1:
 pcpu_update_empty_pages mm/percpu.c:575 [inline]
 pcpu_chunk_populated+0xed/0x110 mm/percpu.c:1483
 pcpu_alloc+0x977/0xcf0 mm/percpu.c:1722
 __alloc_percpu+0x2e/0x40 mm/percpu.c:1796
 xt_percpu_counter_alloc+0x105/0x130 net/netfilter/x_tables.c:1842
 find_check_entry.isra.0+0x64/0x590 net/ipv6/netfilter/ip6_tables.c:546
 translate_table+0x7a5/0xcd0 net/ipv6/netfilter/ip6_tables.c:734
 ip6t_register_table+0xc3/0x210 net/ipv6/netfilter/ip6_tables.c:1782
 ip6table_raw_table_init+0xca/0xe0 net/ipv6/netfilter/ip6table_raw.c:63
 xt_find_table_lock+0x226/0x300 net/netfilter/x_tables.c:1223
 xt_request_find_table_lock+0x35/0xc0 net/netfilter/x_tables.c:1253
 get_info+0xcb/0x430 net/ipv6/netfilter/ip6_tables.c:981
 do_ip6t_get_ctl+0xbf/0x640 net/ipv6/netfilter/ip6_tables.c:1705
 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
 nf_getsockopt+0x71/0xb0 net/netfilter/nf_sockopt.c:122
 ipv6_getsockopt net/ipv6/ipv6_sockglue.c:1400 [inline]
 ipv6_getsockopt+0x17c/0x1d0 net/ipv6/ipv6_sockglue.c:1380
 tcp_getsockopt net/ipv4/tcp.c:3692 [inline]
 tcp_getsockopt+0x7c/0xc0 net/ipv4/tcp.c:3686
 sock_common_getsockopt+0x67/0x90 net/core/sock.c:3108
 __sys_getsockopt+0xf1/0x210 net/socket.c:2162
 __do_sys_getsockopt net/socket.c:2177 [inline]
 __se_sys_getsockopt net/socket.c:2174 [inline]
 __x64_sys_getsockopt+0x70/0x90 net/socket.c:2174
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff86253180 of 4 bytes by task 8109 on cpu 0:
 pcpu_alloc+0x3b0/0xcf0 mm/percpu.c:1729
 __alloc_percpu_gfp+0x31/0x50 mm/percpu.c:1783
 fib_nh_common_init+0x58/0x1e0 net/ipv4/fib_semantics.c:572
 fib6_nh_init+0x2ca/0x1090 net/ipv6/route.c:3470
 ip6_route_info_create+0x9cd/0xe40 net/ipv6/route.c:3659
 ip6_route_add+0x30/0x110 net/ipv6/route.c:3699
 addrconf_prefix_route.isra.0+0x1e3/0x260 net/ipv6/addrconf.c:2396
 fixup_permanent_addr net/ipv6/addrconf.c:3439 [inline]
 addrconf_permanent_addr net/ipv6/addrconf.c:3463 [inline]
 addrconf_notify+0xff0/0x1550 net/ipv6/addrconf.c:3533
 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
 call_netdevice_notifiers_extack net/core/dev.c:1905 [inline]
 call_netdevice_notifiers net/core/dev.c:1919 [inline]
 __dev_notify_flags+0xcf/0x200 net/core/dev.c:8143
 dev_change_flags+0xb8/0xe0 net/core/dev.c:8179
 do_setlink+0x64b/0x1ee0 net/core/rtnetlink.c:2591
 __rtnl_newlink+0x950/0x1090 net/core/rtnetlink.c:3238
 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_sendto+0x21f/0x320 net/socket.c:1985
 __do_sys_sendto net/socket.c:1997 [inline]
 __se_sys_sendto net/socket.c:1993 [inline]
 __x64_sys_sendto+0x89/0xb0 net/socket.c:1993
 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: 8109 Comm: syz-executor.5 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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