general protection fault

If the bit is set, the program does not have access and the processor generates a general protection fault.

General protection faults are caught and handled by modern operating systems.

Attempting to use addresses falling outside this range will cause a general protection fault.

The last one in the list is always the which displayes the General protection fault error message.

Typical error messages you may encounter often include references to general protection faults and Kernel32.

If a program which is not part of the operating system attempts to use one of these features, it may cause a general protection fault.

General Protection Fault has taken part in several fictional crossovers with other online comics.

An attempt to read or write the debug registers when executing at any other privilege level causes a general protection fault.

Other causes of general protection faults are:

A general protection fault would be produced, indicating a segmentation violation had occurred; however, the system would often crash anyway.

In Microsoft Windows, the general protection fault presents with varied language, depending on product version:

In terms of the x86 architecture, general protection faults are specific to segmentation-based protection when it comes to memory accesses.

Vectors 0-31 are reserved by Intel for processor generated exceptions (general protection fault, page fault, etc.).

A general protection fault is implemented as an interrupt (vector number 13 in decimal) in both x86 and AMD64 architectures.

There, pointers must conform to certain rules (canonical addresses), so if a noncanonical pointer is dereferenced, the processor raises a general protection fault.

This message is displayed by Microsoft Windows XP when a program causes a general protection fault or invalid page fault.

With the Beavis and Butt-head Multimedia Screen Saver and Windows 95, Microsoft informs us, "General protection faults can occur when running this program overnight."

The Crash Protector, which by default always runs in the background, guards against software crashes and those G.P.F.'s (General Protection Faults) that Windows likes to test us with.

However, general protection faults are still used to report other protection violations (aside from memory access violations) when paging is used, such as the use of instructions not accessible from the current privilege level.

With Dr. Watson loaded in the system tray, whenever a software fault occurs (general protection fault, hang, etc.), Dr. Watson will intercept it and indicate what software crashed and its cause.

CLI and STI are privileged instructions, which trigger a general protection fault if an unprivileged application attempts to execute it, while POPF will simply not modify the IF flag if the application is unprivileged.

However, many modern operating systems implement their memory access-control schemes via paging instead of segmentation, so it is often the case that invalid memory references in operating systems such as Windows are reported via page faults instead of general protection faults.

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).

This is especially the case if the program writes data to memory pointed by a dangling pointer, a silent corruption of unrelated data may result, leading to subtle bugs that can be extremely difficult to find, or cause segmentation faults (UNIX, Linux) or general protection faults (Windows).

General protection faults are raised by the processor when a protected instruction is encountered which exceeds the permission level of the currently executing task - either because a user-mode program is attempting a protected instruction, or because the operating system has issued a request which would put the processor into an undefined state.