syzbot

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

read-write to 0xffffffff85c537c8 of 4 bytes by task 19402 on cpu 0:
 free_pid+0x71/0x180 kernel/pid.c:136
 copy_process+0x1954/0x2100 kernel/fork.c:2507
 kernel_clone+0x166/0x550 kernel/fork.c:2671
 __do_sys_clone kernel/fork.c:2812 [inline]
 __se_sys_clone kernel/fork.c:2796 [inline]
 __x64_sys_clone+0xc3/0xf0 kernel/fork.c:2796
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff85c537c8 of 4 bytes by task 1842 on cpu 1:
 copy_process+0x1538/0x2100 kernel/fork.c:2420
 kernel_clone+0x166/0x550 kernel/fork.c:2671
 user_mode_thread+0x6c/0xa0 kernel/fork.c:2747
 call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
 call_usermodehelper_exec_work+0x76/0x150 kernel/umh.c:167
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

value changed: 0x80000102 -> 0x80000101

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1842 Comm: kworker/u4:5 Not tainted 6.1.0-rc8-syzkaller-00018-g479174d402bc-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: events_unbound call_usermodehelper_exec_work
==================================================================