==================================================================
BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff8685feb8 of 4 bytes by task 16666 on cpu 0:
 free_pid+0x77/0x180 kernel/pid.c:127
 free_pids+0x7a/0xb0 kernel/pid.c:160
 release_task+0x9a9/0xb60 kernel/exit.c:296
 exit_notify kernel/exit.c:778 [inline]
 do_exit+0xd81/0x15c0 kernel/exit.c:978
 kthread_exit+0x94/0x190 kernel/kthread.c:336
 kthread+0xc7/0x510 kernel/kthread.c:429
 ret_from_fork+0x11f/0x1b0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff8685feb8 of 4 bytes by task 2 on cpu 1:
 copy_process+0x17fc/0x2000 kernel/fork.c:2354
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2609
 kernel_thread+0xad/0xe0 kernel/fork.c:2670
 create_kthread kernel/kthread.c:486 [inline]
 kthreadd+0x28d/0x360 kernel/kthread.c:846
 ret_from_fork+0x11f/0x1b0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x8000019a -> 0x80000199

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2 Comm: kthreadd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================