Linux overlord Linus Torvalds has released Linux 4.9.

“I'm pretty sure this is the biggest release we've ever had, at least in number of commits,” Torvalds writes on the Linux Kernel Mailing List.

“If you look at the number of lines changed, we've had bigger releases in the past, but they have tended to be due to specific issues (v4.2 got a lot of lines from the AMD GPU register definition files, for example, and we've had big re-organizations that caused a lot of lines in the past: v3.2 was big due to staging, v3.7 had the automated uapi header file disintegration, etc).”

“In contrast, 4.9 is just big.”

A lot of the bulk is due to “greybus”, the remnants of Google's Project Ara modular mobile phone that made it into this release.

Other notable additions this time around include:

Support for the Raspberry Pi Zero, plus another 28 ARM-powered devices;

Support for Vmapped stacks, which will mean kernel stack overflows are identified immediately rather than being diagnosed as out-of-the-ordinary. The result: better security;

Implementing memory protection keys, which allows protection of pages;

AMDGPU support to enable use of virtual displays from GPUs.

Torvalds has also confirmed a small change to the development process for Linux 4.10, in the form of a shorter-than-usual merge window. As we identified last week , the usual two-week merge window would close on December 25th.

“That date may look familiar,” Torvalds posted to the Linux Kernel Mailing List. “It's Christmas Day. If you're originally from Finland like me, it's the day when you relax after the real celebrations, which would be on Christmas Eve.”

He's therefore urging kernel developers to get merging, because “I will certainly stop pulling on the 23rd at the latest, and if I get roped into xmas food prep, even that date might be questionable.”

So don't overcook things, Linux devs! ®