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BUG: KCSAN: data-race in free_kthread_struct / kthread_is_per_cpu

write to 0xffff8881098a2c68 of 8 bytes by task 18516 on cpu 1:
 free_kthread_struct+0x5f/0xa0 kernel/kthread.c:143
 begin_new_exec+0xf57/0x1430 fs/exec.c:1313
 load_elf_binary+0x556/0x2560 fs/binfmt_elf.c:1002
 search_binary_handler fs/exec.c:1727 [inline]
 exec_binprm+0x1d9/0x720 fs/exec.c:1768
 bprm_execve+0x3b5/0x520 fs/exec.c:1837
 kernel_execve+0x64e/0x680 fs/exec.c:1998
 call_usermodehelper_exec_async+0x1a6/0x250 kernel/umh.c:112
 ret_from_fork+0x1f/0x30

read to 0xffff8881098a2c68 of 8 bytes by task 18492 on cpu 0:
 __to_kthread kernel/kthread.c:92 [inline]
 kthread_is_per_cpu+0x18/0x80 kernel/kthread.c:606
 can_migrate_task+0xf/0x180 kernel/sched/fair.c:7806
 detach_tasks+0xab/0x3a0 kernel/sched/fair.c:7970
 load_balance+0x7d3/0xcf0 kernel/sched/fair.c:9959
 newidle_balance+0x174/0x350 kernel/sched/fair.c:10968
 pick_next_task_fair+0x37/0x260 kernel/sched/fair.c:7386
 __pick_next_task kernel/sched/core.c:5695 [inline]
 pick_next_task kernel/sched/core.c:6198 [inline]
 __schedule+0x270/0x6c0 kernel/sched/core.c:6346
 schedule+0x71/0xa0 kernel/sched/core.c:6454
 do_wait+0x51f/0x680 kernel/exit.c:1536
 kernel_wait4+0x14b/0x1b0 kernel/exit.c:1680
 __do_sys_wait4 kernel/exit.c:1708 [inline]
 __se_sys_wait4 kernel/exit.c:1704 [inline]
 __x64_sys_wait4+0x90/0x120 kernel/exit.c:1704
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff888123ab6280 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18492 Comm: dhcpcd-run-hook Not tainted 5.17.0-syzkaller-07593-g52deda9551a0-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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