[$] A helper library for BPF arenas

BPF arenas are areas of memory (potentially shared with user space)where programs have free reign to build theirown data structures, unburdened by the verifier's bounds checks. Many of thosedata structures are potentially usable in multiple programs. Emil Tsalapatisbrought his work on libarena, a library containing generic utilities for use inBPF arenas, to the 2026Linux Storage, Filesystem, Memory-Management, and BPFSummit. Although the library is already available as part of the kernel, itis still in its early stages and he has more work planned.