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BUG: KCSAN: data-race in pcpu_alloc_noprof / pcpu_block_update_hint_alloc

read-write to 0xffffffff88be03ac of 4 bytes by task 3314 on cpu 1:
 pcpu_update_empty_pages mm/percpu.c:602 [inline]
 pcpu_block_update_hint_alloc+0x5db/0x6a0 mm/percpu.c:923
 pcpu_alloc_area+0x488/0x4b0 mm/percpu.c:1258
 pcpu_alloc_noprof+0x4bb/0x10a0 mm/percpu.c:1834
 xt_percpu_counter_alloc+0x79/0x110 net/netfilter/x_tables.c:1931
 find_check_entry net/ipv6/netfilter/ip6_tables.c:545 [inline]
 translate_table+0x9b1/0x1040 net/ipv6/netfilter/ip6_tables.c:733
 ip6t_register_table+0x9a/0x440 net/ipv6/netfilter/ip6_tables.c:1751
 ip6table_mangle_table_init+0x4e/0x70 net/ipv6/netfilter/ip6table_mangle.c:85
 xt_find_table_lock+0x19b/0x2b0 net/netfilter/x_tables.c:1260
 xt_request_find_table_lock+0x26/0xa0 net/netfilter/x_tables.c:1285
 get_info net/ipv6/netfilter/ip6_tables.c:979 [inline]
 do_ip6t_get_ctl+0x554/0xc00 net/ipv6/netfilter/ip6_tables.c:1668
 nf_getsockopt+0x18c/0x1b0 net/netfilter/nf_sockopt.c:116
 ipv6_getsockopt+0x172/0x1e0 net/ipv6/ipv6_sockglue.c:1493
 tcp_getsockopt+0xaa/0xe0 net/ipv4/tcp.c:4670
 sock_common_getsockopt+0x5b/0x70 net/core/sock.c:3776
 do_sock_getsockopt+0x1ca/0x260 net/socket.c:2396
 __sys_getsockopt+0x18a/0x200 net/socket.c:2425
 __do_sys_getsockopt net/socket.c:2435 [inline]
 __se_sys_getsockopt net/socket.c:2432 [inline]
 __x64_sys_getsockopt+0x66/0x80 net/socket.c:2432
 x64_sys_call+0x11cd/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:56
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88be03ac of 4 bytes by task 3320 on cpu 0:
 pcpu_alloc_noprof+0x9b6/0x10a0 mm/percpu.c:1894
 fib_nh_common_init+0x4a/0x2b0 net/ipv4/fib_semantics.c:590
 fib_nh_init+0x64/0x1b0 net/ipv4/fib_semantics.c:629
 fib_create_info+0xa1f/0x14f0 net/ipv4/fib_semantics.c:1495
 fib_table_insert+0x101/0xfa0 net/ipv4/fib_trie.c:1237
 fib_magic+0x1a1/0x1f0 net/ipv4/fib_frontend.c:1104
 fib_add_ifaddr+0xd5/0x330 net/ipv4/fib_frontend.c:1126
 fib_netdev_event+0x34f/0x430 net/ipv4/fib_frontend.c:1486
 notifier_call_chain kernel/notifier.c:93 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:461
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:1996
 __dev_notify_flags+0xff/0x1a0
 dev_change_flags+0xab/0xd0 net/core/dev.c:8922
 do_setlink+0x844/0x2490 net/core/rtnetlink.c:2929
 __rtnl_newlink net/core/rtnetlink.c:3725 [inline]
 rtnl_newlink+0x11a3/0x1690 net/core/rtnetlink.c:3772
 rtnetlink_rcv_msg+0x6aa/0x710 net/core/rtnetlink.c:6675
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2551
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6693
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x599/0x670 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x5cc/0x6e0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:729 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:744
 __sys_sendto+0x1d6/0x260 net/socket.c:2214
 __do_sys_sendto net/socket.c:2226 [inline]
 __se_sys_sendto net/socket.c:2222 [inline]
 __x64_sys_sendto+0x78/0x90 net/socket.c:2222
 x64_sys_call+0x2959/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000004 -> 0x00000003

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3320 Comm: syz-executor Not tainted 6.12.0-rc6-syzkaller-00169-g906bd684e4b1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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