Edit to add: no need to read the LWN comments, the article is crystal clear and to the point - no technical reading skills necessary (unlike some very involved Project Zero posts).

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Make sure you get down to the comment by ardbiesheuvel, “linear map randomization was already broken”, past all the hot air about the lack of QA. This comment explains why hot pluggable memory causes issues with randomization.

Now off to read the article.

I’m a bit confused by your edit and I’m glad I ignored it to read the comment you initially highlighted because it does offer a strong counter to the Project Zero article.

There are some good points around how limited the entropy available here is, but it entirely skips over who the fuck needs hotplug memory in the first place. That is a very niche feature that has no application in the vast majority of devices and should never inform the defaults.

It made it very clear - virtualization builds where memory can be dynamically added and removed by the emulator. I haven't done this with Android but it can be quite useful for running lots of test emulators, they can adapt their memory to the workload to not overwhelm the host.

So you agree, it has no place or purpose when running on an actual device.