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BUG: KCSAN: data-race in pcpu_alloc_noprof / pcpu_block_update_hint_alloc

read-write to 0xffffffff8864e61c of 4 bytes by task 3084 on cpu 0:
 pcpu_update_empty_pages mm/percpu.c:602 [inline]
 pcpu_block_update_hint_alloc+0x5db/0x6a0 mm/percpu.c:923
 pcpu_alloc_area+0x488/0x4b0 mm/percpu.c:1258
 pcpu_alloc_noprof+0x4b3/0x10c0 mm/percpu.c:1834
 xt_percpu_counter_alloc+0x79/0x110 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
 ipt_register_table+0x9a/0x430 net/ipv4/netfilter/ip_tables.c:1742
 iptable_nat_table_init+0x42/0x290 net/ipv4/netfilter/iptable_nat.c:115
 xt_find_table_lock+0x194/0x260 net/netfilter/x_tables.c:1260
 xt_request_find_table_lock+0x26/0xa0 net/netfilter/x_tables.c:1285
 get_info net/ipv4/netfilter/ip_tables.c:963 [inline]
 do_ipt_get_ctl+0x554/0xbe0 net/ipv4/netfilter/ip_tables.c:1659
 nf_getsockopt+0x18c/0x1b0 net/netfilter/nf_sockopt.c:116
 ip_getsockopt+0x12a/0x170 net/ipv4/ip_sockglue.c:1777
 tcp_getsockopt+0xaa/0xe0 net/ipv4/tcp.c:4409
 sock_common_getsockopt+0x5b/0x70 net/core/sock.c:3708
 do_sock_getsockopt+0x121/0x1a0 net/socket.c:2386
 __sys_getsockopt+0x19a/0x210 net/socket.c:2415
 __do_sys_getsockopt net/socket.c:2425 [inline]
 __se_sys_getsockopt net/socket.c:2422 [inline]
 __x64_sys_getsockopt+0x66/0x80 net/socket.c:2422
 x64_sys_call+0x128f/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:56
 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 0xffffffff8864e61c of 4 bytes by task 3165 on cpu 1:
 pcpu_alloc_noprof+0x9a7/0x10c0 mm/percpu.c:1894
 fib_nh_common_init+0x4a/0x2b0 net/ipv4/fib_semantics.c:591
 fib6_nh_init+0xea2/0x15c0 net/ipv6/route.c:3622
 ip6_route_info_create+0x7b2/0xba0 net/ipv6/route.c:3809
 ip6_route_add+0x26/0x120 net/ipv6/route.c:3853
 addrconf_add_mroute net/ipv6/addrconf.c:2550 [inline]
 addrconf_add_dev+0x1c6/0x240 net/ipv6/addrconf.c:2568
 addrconf_dev_config net/ipv6/addrconf.c:3482 [inline]
 addrconf_init_auto_addrs+0x497/0x6b0 net/ipv6/addrconf.c:3570
 addrconf_notify+0x7ae/0x950 net/ipv6/addrconf.c:3743
 notifier_call_chain kernel/notifier.c:93 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:461
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:1994
 netdev_state_change+0x80/0xc0 net/core/dev.c:1376
 linkwatch_do_dev+0xb9/0xf0 net/core/link_watch.c:177
 __linkwatch_run_queue+0x284/0x510 net/core/link_watch.c:234
 linkwatch_event+0x40/0x50 net/core/link_watch.c:277
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x700 kernel/workqueue.c:3390
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00000002 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3165 Comm: kworker/1:5 Not tainted 6.10.0-syzkaller-11323-g7846b618e0a4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Workqueue: events linkwatch_event
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