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use-after-free
A bug where a program keeps using a piece of memory after it has already been handed back and freed.
When memory is freed it may be reused for something else, so touching it afterward reads or corrupts unrelated data — sometimes silently, sometimes with a crash, and sometimes as a security hole. These bugs are notoriously hard to catch because the memory often still looks valid for a while. In QTX-0007 a use-after-free was found on tick-stream shutdown; a real Kfree turned a previously silent one into an outright crash, making it visible.
See also
- zombie reapingCleaning up finished child processes that still occupy a slot in the process table.
- userspaceThe world where ordinary programs run, kept separate from the privileged core of the operating system.