The GATE Grind

GATE 2023 CS – Question 23

Operating System · System Calls, Processes, Threads and IPC · 1 mark · Multiple select

Which one or more of the following options guarantee that a computer system will transition from user mode to kernel mode?

  1. Function Call
  2. malloc Call
  3. Page Fault
  4. System Call

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Show answer and explanation

Correct answer: (C) Page Fault; (D) System Call

Explanation

A system call (trap) and a page fault (exception) always switch to kernel mode. An ordinary function call or malloc may be served entirely in user space.