syzbot

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

read-write to 0xffffffff86860018 of 4 bytes by task 11503 on cpu 0:
 free_pid+0xb9/0x1d0 kernel/pid.c:126
 free_pids+0x7a/0xb0 kernel/pid.c:159
 release_task+0x9b1/0xb70 kernel/exit.c:297
 exit_notify kernel/exit.c:779 [inline]
 do_exit+0xd91/0x15d0 kernel/exit.c:985
 call_usermodehelper_exec_async+0x247/0x250 kernel/umh.c:122
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffffffff86860018 of 4 bytes by task 31 on cpu 1:
 copy_process+0x16d4/0x1ef0 kernel/fork.c:2351
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2608
 user_mode_thread+0x7d/0xb0 kernel/fork.c:2684
 call_usermodehelper_exec_work+0x41/0x160 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x80000186 -> 0x80000185

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 31 Comm: kworker/u8:1 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound call_usermodehelper_exec_work
==================================================================