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BUG: KCSAN: data-race in alloc_pid / copy_process

read-write to 0xffffffff86c5c3a8 of 4 bytes by task 15141 on cpu 1:
 alloc_pid+0x6ca/0x950 kernel/pid.c:332
 copy_process+0x11a5/0x2370 kernel/fork.c:2280
 kernel_clone+0x1a5/0x5e0 kernel/fork.c:2721
 user_mode_thread+0x9c/0xd0 kernel/fork.c:2797
 call_usermodehelper_exec_sync kernel/umh.c:132 [inline]
 call_usermodehelper_exec_work+0x7a/0x160 kernel/umh.c:163
 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

read to 0xffffffff86c5c3a8 of 4 bytes by task 14419 on cpu 0:
 copy_process+0x1af1/0x2370 kernel/fork.c:2442
 kernel_clone+0x1a5/0x5e0 kernel/fork.c:2721
 user_mode_thread+0x9c/0xd0 kernel/fork.c:2797
 call_usermodehelper_exec_sync kernel/umh.c:132 [inline]
 call_usermodehelper_exec_work+0x7a/0x160 kernel/umh.c:163
 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: 0x80000149 -> 0x8000014a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 14419 Comm: kworker/u8:21 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound call_usermodehelper_exec_work
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