I think the author uses a hyperbolistic title, but if you read the article it s addressed that there are ways it can fail.
The larger point is that very few users of malloc understand its semantics, and in fact you can't know exactly how malloc will behave without knowing things about the runtime configuration of the system (as opposed to the hardware availability as many people like to think the simple case is).
The larger point is that very few users of malloc understand its semantics, and in fact you can't know exactly how malloc will behave without knowing things about the runtime configuration of the system (as opposed to the hardware availability as many people like to think the simple case is).