syzbot

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BUG: KCSAN: data-race in pcpu_alloc / pcpu_free_area

read-write to 0xffffffff86eeb29c of 4 bytes by task 3111 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+0x4e2/0x570 mm/percpu.c:1302
 free_percpu+0x1c9/0xb20 mm/percpu.c:2276
 xt_percpu_counter_free+0x63/0x70 net/netfilter/x_tables.c:1950
 cleanup_entry+0x18a/0x1b0 net/ipv6/netfilter/ip6_tables.c:671
 __do_replace+0x473/0x580 net/ipv6/netfilter/ip6_tables.c:1099
 do_replace net/ipv6/netfilter/ip6_tables.c:1154 [inline]
 do_ip6t_set_ctl+0x14e4/0x17d0 net/ipv6/netfilter/ip6_tables.c:1636
 nf_setsockopt+0x18d/0x1b0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x11c/0x130 net/ipv6/ipv6_sockglue.c:1017
 tcp_setsockopt+0x90/0xa0 net/ipv4/tcp.c:3677
 sock_common_setsockopt+0x61/0x70 net/core/sock.c:3699
 __sys_setsockopt+0x1d7/0x240 net/socket.c:2308
 __do_sys_setsockopt net/socket.c:2319 [inline]
 __se_sys_setsockopt net/socket.c:2316 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2316
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff86eeb29c of 4 bytes by task 3124 on cpu 0:
 pcpu_alloc+0xa59/0x12a0 mm/percpu.c:1870
 __alloc_percpu_gfp+0x26/0x30 mm/percpu.c:1932
 __percpu_counter_init_many+0x3c/0x1f0 lib/percpu_counter.c:164
 mm_init+0x57f/0x6b0 kernel/fork.c:1307
 dup_mm kernel/fork.c:1683 [inline]
 copy_mm+0x11c/0xff0 kernel/fork.c:1735
 copy_process+0x1008/0x2180 kernel/fork.c:2501
 kernel_clone+0x169/0x560 kernel/fork.c:2909
 __do_sys_clone kernel/fork.c:3052 [inline]
 __se_sys_clone kernel/fork.c:3036 [inline]
 __x64_sys_clone+0xe8/0x120 kernel/fork.c:3036
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000003 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3124 Comm: syz-executor.4 Not tainted 6.6.0-rc1-syzkaller-00033-g3669558bdf35 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
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