BUG: KCSAN: data-race in pcpu_alloc_noprof / pcpu_free_area

read-write to 0xffffffff88bdf3ac of 4 bytes by task 4890 on cpu 0:
 pcpu_update_empty_pages mm/percpu.c:602 [inline]
 pcpu_block_update_hint_free mm/percpu.c:1044 [inline]
 pcpu_free_area+0x4dc/0x570 mm/percpu.c:1302
 free_percpu+0x1c6/0xb30 mm/percpu.c:2246
 xt_percpu_counter_free+0x63/0x80 net/netfilter/x_tables.c:1951
 cleanup_entry+0x195/0x1c0 net/ipv6/netfilter/ip6_tables.c:671
 __do_replace+0x470/0x580 net/ipv6/netfilter/ip6_tables.c:1099
 do_replace net/ipv6/netfilter/ip6_tables.c:1158 [inline]
 do_ip6t_set_ctl+0x820/0x8c0 net/ipv6/netfilter/ip6_tables.c:1644