Linux kernel development manager Linus Torvalds’ prediction that Linux 5.17 would be released this week “unless something surprising happens” has come true. Not in a good way.
The surprise was CVE-2021-26341 – a flaw in some AMD processors that introduced new Spectre and Meltdown-like speculative execution issues. AMD described the flaw as meaning that its processors “may transiently execute instructions following an unconditional direct branch that may result in detectable cache activity.”
While the flaw was only rated 4.7/10 on the CVSS scale and AMD found no active exploits, the chipmaker warned that the issue is present in 14 client CPUs and EPYC silicon. first and second generation for servers. The issue was detected in October 2021 and detailed by Grsecurity, who after the disclosure worked to deliver a fix by February 8, but then agreed to an extended deadline of March 8.
Torvalds said the patches that arrived for the kernel before the March deadline “were mostly correct” and that the flaw “wasn’t one of the ‘big speculations’. But the embargo meant that the automated tests found “a (small) burst of fixes for fixes”.
“None of this was really surprising, but I naively thought I’d be able to make the final version this weekend anyway,” Torvalds wrote. The Emperor Penguin still considered shipping 5.17, but decided “we really have no reason not to give it another week with all the proper automated testing”.
Torvalds also wants developers to pitch in.
“Anyway, let’s not limit testing _just_ to automation,” he suggested in his weekly kernel progress update. “The more the better, and real loads are always more interesting than what automation farms are doing. So please try this latest rc soon,” he said. added.
Release Candidate 8 also includes what Torvalds described as “a few stray fixes that were on the regression list.”
So the signs are very good for a March 20 launch of kernel version 5.17, which lays the foundation for Intel’s Raptor Lake processors among many other improvements. The register looking forward to version 5.18, as this is the version that should reveal more of the software-defined silicon technology that Intel has teased but refused to explain. ®