Linux creator and kernel maintainer Linus Torvalds recently made outspoken comments on the Linux kernel mailing list thread criticizing changes made to the kernel purely to account for buggy hardware and theoretical attacks, per Phoronix. This was prompted by proposed code that Torvalds pointed out likely wouldn’t work with Intel Arrow Lake and Lunar Lake CPUs due to their use of Linear Address Masking (LAM), an Intel feature allowing software to use untranslated address bits for metadata within 64-bit linear addresses.
“Honestly,” Linus Torvalds starts his reply, “I’m pretty damn fed up with buggy hardware and completely theoretical attacks that have never actually shown themselves to be used in practice.”
He continues, “So I think this time we push back on the hardware people and tell them it’s *THEIR* damn problem, and if they can’t even be bothered to say yay-or-nay, we just sit tight.”
Finally, Torvalds declares angrily, “Because dammit, let’s put the onus on where the blame lies, and not just take any random shit from bad hardware and say ‘oh, but it *might* be a problem.'”
Yesterday morning, Intel engineer Kirill Shitemov also commented on that thread, clarifying that “LAM brings own speculation issues that is going to be addressed by LASS. There was a patch to disable LAM until LASS is landed, but it never got applied for some reason.” Per Phoronix, “LASS is the Linear Space Separation Support as a new security feature to prevent malicious virtual address space accesses across user/kernel mode.”
This seems to address Linus’ concerns at least somewhat, but of course, we’ll need long-term hindsight to determine how much this actually changes Linux kernel maintenance moving forward.
Torvalds’ comments do add some additional Free and Open Source Software (FOSS)-centric context to the widespread controversies around Intel’s 13th and 14th Gen CPU failures and widespread. Performance-impacting CPU security mitigations, though. Unlike these giant tech companies that are at least being paid to deal with these things, FOSS developers are under constant pressure to update projects to be compatible with hardware that is sometimes genuinely defective in its design.
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