SYSCALL - multitasking & Interruput event

Dear OxAX ,
Thanks for your efforts for writing "Linux Inside" . It has cleared most of my doubts.
I request you to please elaborate few technical doubts about System call .

1. System call in multitasking environment :
a. What will happen if higher priority task need system resources by SYSCALL but already lower priority task's SYSCALL in running ( kernel code is executing ) ?

b. During one system call multitasking / multi threading is still possible or only one thread will have access to SYSCALL ?

2. System call during External / Peripheral interrupt :
a. what will happen if external interrupt or higher priority pheripheral interrupt triggers while processing SYSCALL ?

Request you to please reply on this & if possible please add explanation in "Linux Inside"

Regards,
Gaurav

This is a request for clarification on Linux kernel internals regarding system calls, multitasking, and interrupts. The issue does not propose a specific change to the repository. To address it, one would need to understand the relevant kernel code (e.g., kernel/sys.c, arch/x86/entry/entry_64.S) and the book's existing content on system calls. The goal would be to draft an explanation or addition to the 'Linux Inside' book.

Written by the indexing model from the issue text.