Cisco has some unusual challenges when it comes to deploying security patches across the company's many devices running custom kernels. John Fastabend spoke about his work preventing exploits with BPF at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit. The technique could substantially reduce the time necessary to respond to kernel vulnerabilities, but it will not be fully effective unless more hooks are added to the kernel.

Debian has announced the final normal update for Debian 12 ("bookworm"). Long-term-support updates will continue until 2028. As may be expected from a stable version, the update is mostly limited to security fixes. Still, it may be time for Debian users to look into upgrading to a more recent version. Conveniently, Debian 13 ("trixie") also received an update this weekend, with many of the same security fixes.

QBE, a compact compiler backend developed by Quentin Carbonneaux, is a lightweight alternative to larger compiler backends such as LLVM and GCC. Designed to be small enough for a single developer to understand, QBE uses a static single-assignment (SSA) intermediate representation (IR), supports the C ABI, and serves as the backend for projects such as Hare and the cproc C11 compiler. Frontends emit the textual form of QBE's IR directly; QBE then takes care of register allocation, optimization, and native-code generation, producing assembly for the target architecture.

Puranjay Mohan shared some of the work he's been doing recently on improving the performance of read-copy-update (RCU) at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit; his talk would have been nice context to have earlier in the day when Harry Yoo and Alexei Starovoitov led a session about the new kmalloc_nolock() function that allows for lockless allocation from any kernel context, and which interacts with the RCU subsystem to allow that. This article therefore covers the two sessions together and in the reverse order, to provide that missing context.

When a BPF program is used to filter or redirect packets in the networking subsystem, the program will often want to associate data with each packet as it moves through the kernel. The kernel's local BPF storage API, which associates extra data with some kernel objects, provides a way to do that. (See also the BPF map types that end in STORAGE.) Amery Hung and Jakub Sitnicki led two sessions at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit about how to make accesses to local storage data more efficient. Hung spoke about general performance problems related to locking, while Sitnicki examined the use of local storage in the networking subsystem in particular.

Lisp-like languages have historically led the world in metaprogramming and flexibility. While many modern languages have adopted the idea of macros, Lisp-like languages such as Racket have continued pushing the envelope, attempting to make macros as easy as possible to incorporate into everyday programs. On the other hand, Lisp's minimal, parenthesis-based syntax can be hard to adapt to — to the point that Lisp is sometimes said to stand for "Lots of Irritating Silly Parentheses". Rhombus is a new programming language that aims to have the best of both worlds, marrying Racket's metaprogramming capabilities to a simple Python-like syntax and reasonable standard-library defaults.

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

Alexis Lothoré has been working to add support for the kernel's memory-access checker, KASAN, to just-in-time-compiled BPF code. He spoke about that work at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit. KASAN support is needed, he said, to help catch bugs in the BPF just-in-time (JIT) compiler. KASAN is a great tool for catching memory-management problems in the kernel, but only in code that can be monitored by it.

BPF programs can be used to extend many aspects the Linux kernel, but BPF programs must run to completion in the same context that they began. Kumar Kartikeya Dwivedi is working on changing that by allowing BPF programs to be expressed as coroutines. He spoke about his work at the 2026 Linux Storage, Filesystem, Memory-Management and BPF Summit. While still experimental, the change promises to make long-running BPF tasks significantly easier to write.

How can cloud providers efficiently supply durable virtual block devices? Remote Direct Memory Access (RDMA) provides a way for servers in a cluster to share chunks of memory, but there still needs to be a protocol that operates on top of RDMA to provide the guarantees expected of a block device. The kernel's RDMA transport library (RTRS) provides a way to send messages via RDMA. I presented about two new components built on top of RTRS at the 2026 Linux Storage, Filesystem, Memory Management and BPF Summit: Reliable Multicast over RTRS (RMR) and Block device over RMR (BRMR). These modules, which I am working on with Jia Li, could be a way for cloud providers to expose durable block devices with as little overhead as possible. To accomplish that, however, we need some discussion and feedback from the community before sending the modules upstream.

The BPF verifier has, in the course of wrestling with the difficult problem of statically analyzing loops, grown special support for many kinds of loops over its history, but its fundamental approach to simple for loops has not changed. When it encounters a loop, it evaluates it, iteration by iteration, until reaching an exit condition — a process that can cause the verifier to mistakenly hit the limit on the number of allowed instructions where a better implementation would not. Eduard Zingerman spoke at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit about his in-progress work on improving the verifier's treatment of loops, especially nested loops.

Alexei Starovoitov gave "less of a presentation, more of a scream of realization" at the BPF track of the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit. He shared a set of ideas for how BPF could change to avoid being swept away by the sea-change in programming represented by modern large language models (LLMs) and the coding agents based on them. In a follow-up session, the discussion covered more problems with how coding agents use tools like bpftrace, and the current deluge of patches in need of review in the BPF subsystem.

Optimizing compilers can, under some circumstances, infer when a parameter to a function is not needed, and remove it. This is all well and good until the kernel's tracing or BPF subsystems need information on how to call the function or where its arguments are stored. Alan Maguire and Yonghong Song spoke at the 2026 Linux Storage, Filesystem, Memory-Management, and BPF Summit about their work on recording information regarding changed function signatures in the kernel's BTF debugging information, to better support tracing such functions.

MeshCore is a relatively new project, started in January 2025, that aims to build a scalable mesh network using low-power long-distance radios. While many other projects of the same general nature have been tried before, MeshCore grew quickly because of its more efficient message routing and enthusiastic community. In early 2026, an early proponent of the project made a sudden shift that left the rest of the community stunned and embroiled in a trademark dispute.

José Marchesi and the GCC-BPF developers opened the BPF track at the 2026 Linux Storage, Filesystem, Memory-management, and BPF Summit with a 90-minute summary of what has changed for GCC's BPF support in the past year. This kind of session has become something of a tradition. There were similar updates in 2025 and 2024. This time around, GCC seems to be closing in on feature parity with the LLVM toolchain — as the slides detail.