==================================================================
BUG: KCSAN: data-race in pcpu_alloc / pcpu_balance_workfn

write to 0xffffffff86dc55a4 of 4 bytes by task 1917 on cpu 0:
 pcpu_update_empty_pages mm/percpu.c:606 [inline]
 pcpu_chunk_populated mm/percpu.c:1534 [inline]
 pcpu_balance_populated mm/percpu.c:2097 [inline]
 pcpu_balance_workfn+0xb04/0xca0 mm/percpu.c:2248
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 worker_thread+0x616/0xa70 kernel/workqueue.c:2445
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

read to 0xffffffff86dc55a4 of 4 bytes by task 2344 on cpu 1:
 pcpu_alloc+0x9c0/0xf80 mm/percpu.c:1878
 __alloc_percpu+0x20/0x30 mm/percpu.c:1950
 tcp_sk_init+0x33/0x750 net/ipv4/tcp_ipv4.c:3117
 ops_init+0x1e7/0x230 net/core/net_namespace.c:140
 setup_net+0x1fb/0x740 net/core/net_namespace.c:326
 copy_net_ns+0x2a9/0x450 net/core/net_namespace.c:470
 create_new_namespaces+0x231/0x560 kernel/nsproxy.c:110
 copy_namespaces+0x116/0x160 kernel/nsproxy.c:178
 copy_process+0x1583/0x2fd0 kernel/fork.c:2194
 kernel_clone+0x15c/0x6a0 kernel/fork.c:2582
 __do_sys_clone kernel/fork.c:2699 [inline]
 __se_sys_clone kernel/fork.c:2683 [inline]
 __x64_sys_clone+0xc6/0xf0 kernel/fork.c:2683
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2344 Comm: syz-executor.5 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================