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BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff86a61ee8 of 4 bytes by task 3412 on cpu 1:
 free_pid+0xb9/0x1d0 kernel/pid.c:126
 free_pids+0x7a/0xb0 kernel/pid.c:159
 release_task+0x9a7/0xb60 kernel/exit.c:295
 exit_notify kernel/exit.c:777 [inline]
 do_exit+0xd56/0x1590 kernel/exit.c:983
 kthread_exit+0x156/0x190 kernel/kthread.c:336
 kthread+0x232/0x280 kernel/kthread.c:469
 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffffffff86a61ee8 of 4 bytes by task 4420 on cpu 0:
 copy_process+0x1895/0x20c0 kernel/fork.c:2396
 kernel_clone+0x16b/0x5b0 kernel/fork.c:2654
 __do_sys_clone kernel/fork.c:2795 [inline]
 __se_sys_clone kernel/fork.c:2779 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2779
 x64_sys_call+0x1222/0x3020 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x800000e4 -> 0x800000e3

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4420 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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