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BUG: KCSAN: data-race in pcpu_alloc / pcpu_free_area

write to 0xffffffff86dc55a4 of 4 bytes by task 1825 on cpu 1:
 pcpu_update_empty_pages mm/percpu.c:606 [inline]
 pcpu_block_update_hint_free mm/percpu.c:1041 [inline]
 pcpu_free_area+0x545/0x5d0 mm/percpu.c:1298
 free_percpu+0x1c5/0x9f0 mm/percpu.c:2284
 xt_percpu_counter_free+0x5f/0x70 net/netfilter/x_tables.c:1950
 cleanup_entry+0x180/0x1b0 net/ipv6/netfilter/ip6_tables.c:673
 __do_replace+0x46e/0x590 net/ipv6/netfilter/ip6_tables.c:1102
 do_replace net/ipv6/netfilter/ip6_tables.c:1157 [inline]
 do_ip6t_set_ctl+0x1514/0x17e0 net/ipv6/netfilter/ip6_tables.c:1639
 nf_setsockopt+0x1a6/0x1c0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x1c92/0x3850 net/ipv6/ipv6_sockglue.c:1017
 tcp_setsockopt+0x8c/0xa0 net/ipv4/tcp.c:3656
 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3478
 __sys_setsockopt+0x209/0x2a0 net/socket.c:2176
 __do_sys_setsockopt net/socket.c:2187 [inline]
 __se_sys_setsockopt net/socket.c:2184 [inline]
 __x64_sys_setsockopt+0x62/0x70 net/socket.c:2184
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff86dc55a4 of 4 bytes by task 1828 on cpu 0:
 pcpu_alloc+0x9c0/0xf80 mm/percpu.c:1878
 __alloc_percpu+0x20/0x30 mm/percpu.c:1950
 xt_percpu_counter_alloc+0x6b/0x110 net/netfilter/x_tables.c:1930
 find_check_entry net/ipv6/netfilter/ip6_tables.c:547 [inline]
 translate_table+0xa08/0x10a0 net/ipv6/netfilter/ip6_tables.c:735
 do_replace net/ipv6/netfilter/ip6_tables.c:1153 [inline]
 do_ip6t_set_ctl+0x14c7/0x17e0 net/ipv6/netfilter/ip6_tables.c:1639
 nf_setsockopt+0x1a6/0x1c0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x1c92/0x3850 net/ipv6/ipv6_sockglue.c:1017
 tcp_setsockopt+0x8c/0xa0 net/ipv4/tcp.c:3656
 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3478
 __sys_setsockopt+0x209/0x2a0 net/socket.c:2176
 __do_sys_setsockopt net/socket.c:2187 [inline]
 __se_sys_setsockopt net/socket.c:2184 [inline]
 __x64_sys_setsockopt+0x62/0x70 net/socket.c:2184
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000003 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1828 Comm: syz-executor.5 Not tainted 5.16.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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