Better linked-list traversal in BPF

Yes, and

> he suggested that the kernel may eventually implement a watchdog timer to simply interrupt programs that run for too long.

It's a long and winding path towards BPF being just a bad version of WebAssembly. (Bad because, among other reasons, it will be encrusted with all these different attempts to avoid just using a watchdog timer, which will have to be supported indefinitely.)