[$] A look at what's possible with BPF arenas
BPF arenas are areas of memory where the verifier can safely relax its checking of pointers, allowing programmers to write arbitrary data structures in BPF. Emil Tsalapatis reported on how his team has used arenas in writing sched_ext schedulers at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit. His biggest complaint was about the fact that kernel pointers can't be stored in BPF arenas — something that the BPF developers hope to address, although there are some implementation problems that must be sorted out first.