syzbot

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BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff86c5c368 of 4 bytes by task 31898 on cpu 0:
 free_pid+0xb3/0x1b0 kernel/pid.c:124
 free_pids+0x7a/0xb0 kernel/pid.c:156
 release_task+0x9a7/0xb60 kernel/exit.c:295
 exit_notify kernel/exit.c:776 [inline]
 do_exit+0xda4/0x1530 kernel/exit.c:987
 call_usermodehelper_exec_async+0x246/0x250 kernel/umh.c:122
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff86c5c368 of 4 bytes by task 3440 on cpu 1:
 copy_process+0x1b1d/0x23a0 kernel/fork.c:2444
 kernel_clone+0x1a5/0x5e0 kernel/fork.c:2723
 user_mode_thread+0x9c/0xd0 kernel/fork.c:2799
 call_usermodehelper_exec_work+0x41/0x160 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
 worker_thread+0x58a/0x780 kernel/workqueue.c:3466
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x80000108 -> 0x80000107

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3440 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound call_usermodehelper_exec_work
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