Why Does My eBPF Program Work on One Kernel but Fail on Another?

In a perfect world, everyone’s systems would be fully updated, patched regularly, and running the latest kernel. But let’s be real—that’s rarely the case. Some environments still rely on legacy versions of Ubuntu or Fedora, while others don't even have their kernels compiled with BTF (BPF Type Format) support. And if you’re maintaining any open-source tools, things get even messier. You have zero control over what kind of system your users will run your program on. All of this makes it tricky to ensure that your eBPF programs can run reliably across different distributions, ultimately affecting whether your eBPF tool gets adopted or not. So how do we make eBPF programs truly portable? To better understand the problem, let’s look at an hypothetical example. Suppose you compile an eBPF program on kernel version 5.3, but it fails to run on 5.4. Why? Because each kernel version ships with its own kernel headers, which define structs and memory layouts. Even small changes in these d ... Read full article.