syzbot

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BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff8605c4f8 of 4 bytes by task 6117 on cpu 1:
 free_pid+0x80/0x170 kernel/pid.c:143
 copy_process+0x19d0/0x1f90 kernel/fork.c:2637
 kernel_clone+0x16a/0x570 kernel/fork.c:2797
 __do_sys_clone3 kernel/fork.c:3098 [inline]
 __se_sys_clone3+0x1b5/0x1f0 kernel/fork.c:3082
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:3082
 x64_sys_call+0x28df/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff8605c4f8 of 4 bytes by task 32659 on cpu 0:
 copy_process+0x15e3/0x1f90 kernel/fork.c:2543
 kernel_clone+0x16a/0x570 kernel/fork.c:2797
 user_mode_thread+0x7d/0xb0 kernel/fork.c:2875
 call_usermodehelper_exec_work+0x41/0x150 kernel/umh.c:172
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x730 kernel/workqueue.c:3393
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x800002a0 -> 0x8000029f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 32659 Comm: kworker/u8:10 Tainted: G        W          6.9.0-syzkaller-12333-g54f71b0369c9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: events_unbound call_usermodehelper_exec_work
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