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CPU exception / trap
The CPU automatically jumping into special handler code when something like a fault or error occurs.
When a running instruction hits a problem — a bad memory access, a divide by zero, a page fault — the processor interrupts normal flow and transfers control to a designated handler. That mechanism is a CPU exception or trap. It runs in a special context, which is why a fault record is written from inside the exception rather than in ordinary code.
See also
- code-segment selectorAn x86 register value that identifies which block of executable memory the CPU is currently running code from.
- context switchThe kernel saving one thread's full state and loading another's, so a single CPU can juggle many tasks.
- critical sectionA stretch of code that must be run by only one thread at a time to avoid corruption.