Andrew Morton, the lead maintainer of the Linux production kernel, is
worried that an increasing number of defects are appearing in the 2.6 version
and is considering drastic action to resolve it.
"I believe the 2.6 kernel is slowly getting buggier. It seems we're adding
bugs at a higher rate than we're fixing them," Morton said in a talk at the
LinuxTag conference in Wiesbaden, Germany, last Friday.
Morton said he hasn't yet proved this statistically, but has noticed that he
is getting more e-mails with bug reports. If he is able to confirm the
increasing defect rate, he may temporarily halt the kernel development process
to spend time resolving issues.
"A little action item I've given myself is to confirm that this increasing
defect rate is really happening," he said. "If it is, we need to do something
"Kernel developers will need to reapportion their time and spend more time
fixing bugs," he added. "We may possibly have a bug fix-only kernel cycle, which
is purely for fixing up long-standing bugs."
One problem is that few developers are motivated to work on defects, Morton
said. This is particularly a problem for bugs that affect old computers or
peripherals, as kernel developers working for corporations don't tend to care
about out-of-date hardware, he said.
Nowadays, many kernel developers are employed by IT companies, such as
hardware manufacturers. That can cause problems, as they may be motivated by
self-interest, Morton suggested.
"If you're a company that employs a kernel maintainer, you don't have an
interest in working on a 5-year-old peripheral that no one is selling any more.
I can understand that, but it is a problem, as people are still using that
hardware. The presence of that bug affects the whole kernel process, and can
hold up the kernel, as there are bugs, but no one is fixing them," he said.
Differences in a kernel
During his talk, Morton discussed the 2.6
kernel development process. He explained that if people want to get their code
into the kernel they should send it to him, and not to Linus Torvalds, who
maintains the development kernel. Morton manages the "-mm" code branch, which is
where patches are tested before being added to the development kernel.
"The way an individual can get their code into the kernel is by sending it to
me. I will buffer it in my (mm) tree and send it to Linus," he said.
"It's fairly rare for a person to send a patch to Linus and get it in. In
fact, Linus is fairly random at patches at the best of times. Generally, Linus
will cc: it to me because he knows I'll pick it up," Morton added.
"The mm tree is what Linus' tree is going to look like in three months time.
A lot of stupid bugs get in. I wish people would send me code that
compiles--probably about 75 percent do," he said. "Without mm, all of these
problems wouldn't be discovered until they hit the mainline tree, and would
impact everyone's ongoing development."
The LinuxTag conference goes on until Saturday. Talks that take place in the
main conference room can be watched online via a free Webcast (instructions in