General Protection Fault

A general protection fault (GPF) in the Intel x86 and AMD x86-64 architectures, and other unrelated architectures, is a fault (a type of interrupt) that can encompass several cases in which protection mechanisms within the processor architecture are violated by any of the programs that are running, either the kernel or a user program. The mechanism is first described in section 9.8.13 in the Intel 80386 programmer's reference manual from 1986. A general protection fault is implemented as an interrupt (vector number 13 in decimal) in both x86 and AMD64 architectures.

If the processor detects a protection violation, it stops executing the code and sends a GPF interrupt. In most cases the operating system will simply remove the failing process from the execution queue, signal the user, and continue executing another program. If however the operating system fails to catch the general protection fault, i.e. another protection violation occurs before the operating system returns from the previous GPF interrupt, the processor will signal a double fault (interrupt vector 8, a typical BSOD scenario). If yet another failure occurs, the processor will shut down (see triple fault). It will then only respond to a reset (that is, pressing the reset-button) or init (rebooting the entire system) and non-maskable interrupts (unless it has previously failed when handling NM interrupts, in which case it will ignore these too).