Linux 7.1 is yanking ham radio, ISDN, and ATM. The reason: AI bug-report spam.

Linux’s networking maintainer Jakub Kicinski sent a pull request on Friday that deletes 138,161 lines of old networking code from the kernel: ISDN, amateur-radio AX.25, CAIF, legacy ATM drivers, and Bluetooth CMTP. The stated motivation isn’t that the code is broken. It’s that large language models keep filing bogus security reports against it and nobody’s left to triage them.

What’s going away

Kicinski’s PR targets the Linux 7.1 merge window, which closes this Sunday, April 26. The list is blunt:

• ISDN subsystem. mISDN and the rest of the old dial-up telephony stack.
• AX.25 and amateur (“ham”) radio. The packet-radio protocols, KISS, NET/ROM, ROSE, and friends.
• CAIF network layer. A protocol ST-Ericsson mainline’d years ago for modems the company no longer ships.
• Legacy ATM protocols and drivers. The old Asynchronous Transfer Mode code, kept around for a handful of Cisco and Fore Systems cards.
• Bluetooth CMTP. The CAPI-over-Bluetooth profile, which hasn’t had an actively-supported product behind it in over a decade.

The removal covers two changesets: Kicinski’s networking tree pull and a parallel cleanup that drops the matching PCMCIA Ethernet and ISA drivers, per Phoronix’s reporting on the broader teardown. It’s one of the biggest single deletions in recent kernel history.

Why now: the AI report flood

Kernel maintainers have been flagging the problem for months. LWN’s coverage of the debate quotes the underlying logic directly: “This set of protocols has long been a huge bug/syzbot magnet, and since nobody stepped up to help us deal with the influx of the AI-generated bug reports we need to move it out of tree to protect our sanity.”

The dynamic is specific. Security researchers point LLMs at old, poorly-maintained corners of the tree. The LLMs produce plausible-looking CVE writeups. Maintainers still have to read each one to rule out a real finding. For a subsystem like AX.25 with, generously, a few hundred active users worldwide, that labor stops making sense.

Mozilla’s Firefox team hit the inverse version of the same problem. Anthropic’s Claude Mythos found 271 real Firefox bugs in Project Glasswing this month. The difference is someone on the Firefox side wanted those reports. Kernel maintainers for unloved protocols don’t.

What hasn’t been cut

The removal isn’t a full “legacy cleanup.” Modern wireless stacks, mainstream Ethernet drivers, and current telephony paths (cellular modems, mainline Bluetooth) all stay. The bar Kicinski is applying is roughly: no active maintainer + no measurable real-world user base + an ongoing AI-bug-report burden.

The Linux 7.1 cycle is shedding other legacy weight at the same time. Torvalds merged code beginning to remove Intel 486 support earlier in the merge window. i486 is following i386 out the door after a decade of effectively being dead silicon.

What’s still uncertain

• Final merge status. At publication, Kicinski’s pull was in Torvalds’s inbox but the net/ branch was still being reviewed. Phoronix’s feed listed a Friday afternoon update noting the removal was merged; the archived article is offline at the moment. We’ll update once the final tag lands.
• Out-of-tree fate. Ham radio operators and the handful of ISDN users aren’t completely stranded. Out-of-tree modules are an option, and the Linux ham-radio community is separately modernizing the KISS serial driver. But an out-of-tree driver is a distribution’s problem to package, not Canonical’s or Red Hat’s default.
• The precedent. If “AI bug-report pressure” becomes an accepted reason to drop subsystems, the next round of deletions is going to be political. Everything from the classic /proc interfaces to old filesystem formats could get pulled into the same conversation.

What this means for you

If you run a modern distro on modern hardware, nothing changes. Ubuntu 26.04 LTS, which shipped Thursday on kernel 7.0, is untouched. Fedora, Debian stable, Arch, and enterprise distros track 7.1+ on their own cadence and will pick up the removals over the next year.

If you actually use ham radio over AX.25, run ISDN anywhere, or have an ATM card in production (you don’t, but if you did), start planning. Pin to the 7.0 LTS line or be ready to maintain an out-of-tree module yourself.

For everyone else, the more interesting signal is the second-order one. Kernel maintainers just formally cited AI-generated noise as a reason to delete working code. That’s a new economic argument in open-source maintenance, and it’s going to keep showing up. If your project has an unloved corner and a patient LLM-powered researcher decides to rake over it, the answer isn’t always going to be “we’ll fix it.” Sometimes it’ll be the PR Kicinski just sent.