• Linus Torvalds Reveals How He Herds the Cats of the Linux Kernel

"Linus has this bad habit of fixing security holes quietly," admitted kernel maintainer Alan Cox during a talk given in Brussels last week during this year's FOSDEM (Free & Open Source Software Developer's European Meeting).

FOSDEM, which was first organized in 2001, is considered a must-attend event by Linux cognoscenti in Europe. Many of LinuxWorld.com's writers over the years either attend or speak.

Alan Cox, a fellow at Red Hat and an early developer and maintainer of the Linux networking code who since coauthoring the original Linux SMP has at various times maintained various official and branch kernel releases, was giving a talk on the challenges of maintaining a stable kernel branch.

In advance of his talk, Cox had said "FOSDEM seems to have a reputation for being a real developer conference so it should be a lot of fun." (He added "I hope the beer is good.")

In the talk itself, he discussed how - though there is no highly critical remote hole right now, we improve the way the security fixes are made to the Linux kernel. There is, for example, no official security maintainer for the base kernel, to handle all the security advisories and bugfixes - areas which are not, Cox admitted, Linus Torvalds' strong suit.

"Linus is a good developer, but is a terrible engineer," he noted, adding that he was sure Torvalds himself would agree with the observation.

Cox went on to reveal that Torvalds "has this bad habit of fixing security holes quietly" - which is not a good idea, in Cox's view.

As a Red Hat fellow Alan Cox is in an enviable position, since he says his employer imposes no contraints:

"Red Hat primarily pays me to work on the kernel. I'm mostly trusted to use my own judgement on what that means, and guided by the hot issues customers see. There are things I get through Red Hat, such as vendor pre-production systems and documents that are restricted but nobody in Red Hat demands I run Red Hat products for example. Except for the little boxes (running Debian) I do run Red Hat Fedora but that's by choice."

Clearly Linux's strength is that it is a building to which many different people have brought a stone. There has been a great improvement between the 2.4 and 2.6 kernel versions, and a lot of developers have been hacking since the first release of the 2.6 kernel.

Alastair Mayer, a software developer and UNIX systems administrator, has described Linus Torvalds' role ver succinctly:

"Linus isn't running the show. He's not paying anybody, he can't fire anybody, he can't make anybody drop one project or idea to work on another. He can direct some developers to do something and they can tell him to take a hike, or they can do it because they think it's a good idea.

More often, though, there are just many ideas (patches, development threads, what have you) to choose from and Linus "rules" by choosing which goes into his kernel. The cathedral is about direction. That isn't what Linus does - he just selects what is best from what the bazaar has produced."

So being a "terrible engineer" isn't quite the handicap it might seem. Besides, Cox and he have been working together for a very long time, and each complements the other and together they make the whole of the Linux kernel better. As one developer recently remarked: "Linus's sense of who's a good dev and who fits into his team well is uncanny."