Linus Torvalds blasts Intel's Meltdown/Spectre patch as "pure garbage"

Linux creator Linus Torvalds has lambasted Intel for the fiasco surrounding its patches for the Meltdown and Spectre flaws, calling the fixes "pure garbage".

In a post on the Linux kernel mailing list, Torvalds said the patches, part of a rollout of updates for chips dating back through the last decade, "do literally insane things" to the performance of the systems they are installed on. Intel itself found that the patches impact performance by up to 25% on data centre chips, and 3% to 4% on other systems.

"They do things that do not make sense," Torvalds said. "That makes all your arguments questionable and suspicious. The patches do things that are not sane. WHAT THE F*CK IS GOING ON?"

He continued to rant that the patches are "ignoring the much worse issue, namely that the whole hardware interface is literally mis-designed by morons".

He added: "All of this is pure garbage," and elsewhere: "And I really don't want to see these garbage patches just mindlessly sent around."

Torvalds' ire appears to be directed at Intel's decision to patch issues that other fixes - like Google's Retpoline fix - already solve - like Google's Retpoline fix addressing a branch target injection enabled by Spectre.

But he also directed his fire at Intel for its plan to remedy the performance hits its patches are creating. Intel's plan seems to be to bypass the performance hits its Indirect Branch Restricted Speculation (IBRS) update causes by making the Meltdown fix optional, introducing it as an additional feature.

"The whole IBRS_ALL feature to me very clearly says 'Intel is not serious about this, we'll have a ugly hack that will be so expensive that we don't want to enable it by default, because that would look bad in benchmarks'," Torvalds wrote. "So instead they try to push the garbage down to us."

IT Pro has approached Intel for comment on Torvalds' outburst.

It comes as Intel decided to advise customersn not to download their patches, due to the reboots and performance hits they were causing.

In a post today on the company's newsroom, the firm's executive vice president, Navin Shenoy, said: "We recommend that OEMs, cloud service providers, system manufacturers, software vendors, and end users stop deployment of current versions on specific platform as they may introduce higher than expected reboots and other unpredictable system behaviour."

The advisory applies to systems powered by Intel's previous generations of chips, including Broadwell, Haswell, Coffee Lake, Kaby Lake, Skylake, and Ivy Bridge families. Intel apologised for the issues being caused by the patch, but it's likely to not be enough for users with suddenly borked machines.

"I apologise for any disruption this change in guidance may cause. The security of our products is critical for Intel, our customers and partners, and for me, personally. I assure you we are working around the clock to ensure we are addressing these issues," he added.