BUG: KCSAN: data-race in pcpu_alloc / pcpu_block_update_hint_alloc

read-write to 0xffffffff884034dc of 4 bytes by task 3111 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+0x49f/0x4d0 mm/percpu.c:1258
 pcpu_alloc+0x4b3/0x10d0 mm/percpu.c:1808
 __alloc_percpu+0x24/0x30 mm/percpu.c:1943
 xt_percpu_counter_alloc+0x72/0x110 net/netfilter/x_tables.c:1931
 find_check_entry net/ipv4/netfilter/ip_tables.c:526 [inline]
 translate_table+0x921/0xf70 net/ipv4/netfilter/ip_tables.c:716
 do_replace net/ipv4/netfilter/ip_tables.c:1137 [inline]
 do_ipt_set_ctl+0x7bd/0x8b0 net/ipv4/netfilter/ip_tables.c:1635
 nf_setsockopt+0x195/0x1b0 net/netfilter/nf_sockopt.c:101
 ip_setsockopt+0xea/0x100 net/ipv4/ip_sockglue.c:1424
 tcp_setsockopt+0x93/0xb0 net/ipv4/tcp.c:3737
 sock_common_setsockopt+0x64/0x80 net/core/sock.c:3727
 do_sock_setsockopt net/socket.c:2311 [inline]
 __sys_setsockopt+0x1d8/0x250 net/socket.c:2334
 __do_sys_setsockopt net/socket.c:2343 [inline]
 __se_sys_setsockopt net/socket.c:2340 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2340
 x64_sys_call+0x1159/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:55
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff884034dc of 4 bytes by task 3101 on cpu 0:
 pcpu_alloc+0x9aa/0x10d0 mm/percpu.c:1868
 __alloc_percpu+0x24/0x30 mm/percpu.c:1943
 xt_percpu_counter_alloc+0x72/0x110 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
 do_replace net/ipv6/netfilter/ip6_tables.c:1154 [inline]
 do_ip6t_set_ctl+0x7cc/0x8c0 net/ipv6/netfilter/ip6_tables.c:1644
 nf_setsockopt+0x195/0x1b0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x126/0x140 net/ipv6/ipv6_sockglue.c:999
 tcp_setsockopt+0x93/0xb0 net/ipv4/tcp.c:3737
 sock_common_setsockopt+0x64/0x80 net/core/sock.c:3727
 do_sock_setsockopt net/socket.c:2311 [inline]
 __sys_setsockopt+0x1d8/0x250 net/socket.c:2334
 __do_sys_setsockopt net/socket.c:2343 [inline]
 __se_sys_setsockopt net/socket.c:2340 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2340
 x64_sys_call+0x1159/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:55
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000a -> 0x00000009

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3101 Comm: syz-executor.1 Not tainted 6.9.0-rc4-syzkaller-00038-g8cd26fd90c1a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.