Privacy

30829 readers

1018 users here now

A place to discuss privacy and freedom in the digital world.

Privacy has become a very important issue in modern society, with companies and governments constantly abusing their power, more and more people are waking up to the importance of digital privacy.

In this community everyone is welcome to post links and discuss topics related to privacy.

Some Rules

Posting a link to a website containing tracking isn't great, if contents of the website are behind a paywall maybe copy them into the post
Don't promote proprietary software
Try to keep things on topic
If you have a question, please try searching for previous discussions, maybe it has already been answered
Reposts are fine, but should have at least a couple of weeks in between so that the post can reach a new audience
Be nice :)

Related communities

Chat rooms

[Matrix/Element]Dead
Discord

much thanks to @gary_host_laptop for the logo design :)

founded 4 years ago

MODERATORS

[email protected]

Encryption-breaking, password-leaking bug in many AMD CPUs could take months to fix (arstechnica.com)

submitted 1 year ago by [email protected] to c/[email protected]

21 comments fedilink hide all child comments

The bug allows attackers to swipe data from a CPU's registers. [...] the exploit doesn't require physical hardware access and can be triggered by loading JavaScript on a malicious website.

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 4 points 1 year ago (1 children)

These would be performance regressions, not correctness errors. Specifically, some false dependencies between instructions. The result of that is that some instructions which could be executed immediately may instead have to wait for a previous instruction to finish, even though they don't actually need its result. In the worst case, this can be really bad for performance, but it doesn't look like the affected instructions are too likely to be bottlenecks. I could definitely be wrong though; I'd want to see some actual data.

The pentium fdiv bug, on the other hand, was a correctness bug and was a catastrophic problem for some workloads.

[–] [email protected] 1 points 1 year ago

Thanks for the clarification!

I remember having to learn about fp representations in a numerical analysis class and some of the things you had to worry about back then, but by the time I ended up doing work where I’d actually have to worry about it, most of the gotchas had been taken care of so I largely stopped paying attention to the topic.