Linus Torvalds muses about maintainer gray hairs and the next 'King of Linux'

VIENNA - In a candid keynote chat at the Linux Foundation's Open Source Summit Europe, Linux creator Linus Torvalds shared his thoughts on kernel development, the integration of Rust, and the future of open source. Dirk Hohndel, Verizon's Open Source Program Office head and Torvalds friend, moderated their conversation about the Linux ecosystem.

Torvalds emphasized that kernel releases, like the recent 6.11 version, are intentionally not exciting. "For almost 15 years, we've had a very good regular cadence of releases," he explained. With releases every nine weeks, this regularity aims for timeliness and reliability rather than flashy new features.

Also: Linux kernel 6.11 is out - with its own BSOD

The Linux creator noted that while drivers still make up the bulk of changes, core kernel development continues to evolve. "I'm still surprised that we're doing very core development," Torvalds said, mentioning ongoing work in virtual file systems and memory management.

The integration of Rust into the Linux kernel has continued to be a hot topic -- even a controversial one. Recently, Wedson Filho, a Microsoft software engineer and one of the Rust for Linux maintainers, quit the project in a note to the Linux Kernel Mailing List (LKML). FIho left, he wrote, because "After almost four years, I find myself lacking the energy and enthusiasm I once had to respond to some of the nontechnical nonsense, so it's best to leave it up to those who still have it in them."

What was he talking about? Inside Linux kernel circles, some developers and maintainers want nothing to do with Rust, and they're not shy about voicing their opinion that the programming language has already failed. 

Even Torvalds, who doesn't mind arguments, admitted, "Some of the arguments get nasty. I'm not quite sure why Rust has been such a contentious area. It reminds me of when I was young. People were arguing about vi versus EMACS. For some reason, the whole Rust versus C discussion has taken almost religious overtones in certain areas."  

Torvalds, however, isn't giving up on Rust. He said:

"Rust is a very different thing, and there are a lot of people who are used to the C model. They don't like the differences, but that's OK. In the kernel itself, absolutely nobody understands everything. I don't. I rely heavily on maintainers of various subsystems. I think the same can be true of Rust and C. I think it's one of our strengths in the kernel that we can specialize. Clearly, some people just don't like the notion of Rust and having Rust encroach on their area. But we've only been doing Rust for a couple of years, so it's way too early to say Rust is a failure." 

So, despite the arguments and the recent loss of a top maintainer, Torvalds remains optimistic about Rust's future in the kernel.

Also: Rust in Linux: Where we are and where we're going next

Hohndel also asked Torvalds, "One of the exciting things that has happened this year is the celebration of the real-time Linux (RTLinux) project -- will it finally be completely in the kernel after a very 'brief' development cycle of about 20 years?" (Yes, RTLinux has been in the oven for that long.)

While RTLinux is an infamously special case, Torvalds confirmed it will happen in the next release, Linux 6.12. "I don't think I have the pull request for the final bits in my mailbox yet, but I'm expecting that to happen this week."

"People think kernel development is very quick," Torvalds continued, "because every three months or so, we have between 10,000 and 15,000 commits going into the kernel. There is a lot of development going on, but a lot of stuff has been developed over months or years, or -- in some cases -- decades. So while kernel development is very active, it doesn't necessarily mean that you can get a new feature, file system, or anything into the kernel very quickly." 

Shifting back to another contentious subject -- maintainer burnout and succession planning -- Hohndel observed that "maintainers are aging. Strangely, some of us have, you know, not quite as much or the right hair color anymore." (Torvalds interjected that "gray is the right color.") Hohndel continued, "So the question that I always ask myself: Is it about time to talk about there being a mini-Linus?"

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Torvalds turned the question around. True, the Linux maintainers are getting older and people do burn out and go away. "But that's kind of normal. What is not normal is that people actually stay around for decades. That's the unusual thing, and I think that's a good sign."

At the same time, Torvalds admitted, it can be intimidating for a younger developer to join the Linux kernel team "when you see all these people who have been around for decades, but at the same time, we have many new developers. Some of those new developers come in, and three years later, they are top maintainers."

Hohndel noted that "to be the king of Linux, the main maintainer, you have to have a lot of experience. And the backup right now is Greg KH (Greg Kroah-Hartman, maintainer of the stable Linux kernel), who is about the same age as we are and has even less hair."

True, Torvalds responded, "But the thing is, Greg hasn't always been Greg. Before Greg, there's been Andrew {Morton) and Alan (Cox). After Greg, there will be Shannon and Steve. The real issue is you have to have a person or a group of people that the development community can trust, and part of trust is fundamentally about having been around for long enough that people know how you work, but long enough does not mean to be 30 years."

Also: Linux and open-source documentation is a mess: Here's the solution

Hohndel made one last comment: "What I'm trying to say is, you've been doing this for 33 years. I don't want to be morbid, but I think in 33 years, you may no longer be doing this?" Torvalds, making motions as though he was using a walker, replied, "I would love to still do this conference with you."

So, while Linux is 33 years old now, Torvalds expects he'll still be maintaining code and making snarky comments for decades to come. Would te Linux community have it any other way?