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BUG: KCSAN: data-race in pcpu_alloc_noprof / pcpu_free_area

read-write to 0xffffffff88be03ac of 4 bytes by task 3317 on cpu 1:
 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+0x186/0x1b0 net/ipv4/netfilter/ip_tables.c:654
 __do_replace+0x467/0x570 net/ipv4/netfilter/ip_tables.c:1082
 do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline]
 do_ipt_set_ctl+0x811/0x8b0 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:4029
 sock_common_setsockopt+0x64/0x80 net/core/sock.c:3809
 do_sock_setsockopt net/socket.c:2334 [inline]
 __sys_setsockopt+0x1cc/0x240 net/socket.c:2357
 __do_sys_setsockopt net/socket.c:2366 [inline]
 __se_sys_setsockopt net/socket.c:2363 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2363
 x64_sys_call+0x278d/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:55
 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 3318 on cpu 0:
 pcpu_alloc_noprof+0x9b6/0x10a0 mm/percpu.c:1894
 mm_alloc_cid_noprof include/linux/mm_types.h:1199 [inline]
 mm_init+0x47f/0x730 kernel/fork.c:1302
 dup_mm kernel/fork.c:1672 [inline]
 copy_mm+0x11e/0x10e0 kernel/fork.c:1724
 copy_process+0xd5b/0x1f90 kernel/fork.c:2374
 kernel_clone+0x167/0x5e0 kernel/fork.c:2786
 __do_sys_clone kernel/fork.c:2929 [inline]
 __se_sys_clone kernel/fork.c:2913 [inline]
 __x64_sys_clone+0xe8/0x120 kernel/fork.c:2913
 x64_sys_call+0x2d23/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:57
 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: 0x00000069 -> 0x0000006a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3318 Comm: syz-executor Not tainted 6.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
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