C compiled down to eBPF (as implemented with the Linux kernel) is not turing-complete. eBPF has a wide variety of uses from network filtering to hooking into certain syscalls.

The bytecode is theoretically turing-complete, but the verifier present in the kernel ensures that the code contains no loops and accesses no out-of-bounds memory.

With `clang`, you can compile C down to eBPF bytecode. It's a subset of C, with a lot of restrictions, but it is familiar and capable of some remarkable things past just simple packet parsing & filtering.