pt_regs usage in cpuacct_charge()

[Pavel V. Panteleev]

Hello!

In cpuacct_charge() function pt_regs of other thread could be used. 
There is a such call chain: ...-> __schedule -> pick_next_task_fair -> 
load_balance -> idle_balance -> load_balance -> detach_tasks -> 
deactivate_task -> dequeue_task_fair -> dequeue_entity -> update_curr -> 
cpuacct_charge.

I think that pt_regs could disappeared or be changed. How it's assumed 
to syncronize pt_regs usage in this place?

Kernel verion 4.9.47-rt47.


Best regards,
Pavel V. Panteleev