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BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff8685fc48 of 4 bytes by task 7865 on cpu 0:
 free_pid+0x77/0x180 kernel/pid.c:126
 free_pids+0x54/0xb0 kernel/pid.c:159
 release_task+0x9a9/0xb60 kernel/exit.c:296
 wait_task_zombie kernel/exit.c:1264 [inline]
 wait_consider_task+0x114a/0x1660 kernel/exit.c:1491
 do_wait_thread kernel/exit.c:1554 [inline]
 __do_wait+0xfa/0x510 kernel/exit.c:1672
 do_wait+0xb7/0x260 kernel/exit.c:1706
 kernel_wait4+0x16b/0x1e0 kernel/exit.c:1865
 __do_sys_wait4 kernel/exit.c:1893 [inline]
 __se_sys_wait4 kernel/exit.c:1889 [inline]
 __x64_sys_wait4+0x91/0x120 kernel/exit.c:1889
 x64_sys_call+0x2a66/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:62
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff8685fc48 of 4 bytes by task 10960 on cpu 1:
 copy_process+0x14a6/0x2000 kernel/fork.c:2348
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2605
 __do_sys_clone kernel/fork.c:2748 [inline]
 __se_sys_clone kernel/fork.c:2732 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2732
 x64_sys_call+0x119c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x800000f2 -> 0x800000f1

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 10960 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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