[$] BPF-based error injection for the kernel

Diligent developers do their best to anticipate things that can go wrongand write appropriate error-handling code. Unfortunately, error-handlingcode is especially hard to test and, as a result, often goes untested; thecode meant to deal with errors, in other words, is likely to contain errorsitself. One way of finding those bugs is to inject errors into a runningsystem and watching how it responds; the kernel may soon have a newmechanism for doing this sort of injection.