Ref: https://labs.vmware.com/vmtj/memory-overcommitment-in-the-es... (search "page sharing")
Should be vulnerable to FFS, if I'm not mistaken: http://arstechnica.com/security/2016/08/new-attack-steals-pr...
It's sort of like when WebGL was first getting going, and the GPUs of the time didn't expect to be fed shaders directly from potentially-malicious web sources. Rather than severely restricting the WebGL API, we got a new generation of GPUs that fail safe.
When Rowhammer was first announced, people said "it's okay, we have ECC". Then ECC was shown vulnerable. "It's okay, vendors have promised to fix it in DDR4", they said. Now DDR4 is out and vendors have not deployed the fixes systematically[1] and you have to benchmark every single RAM stick to make sure you're not vulnerable.
I'd really appreciate software workarounds as long as hardware vendors keep fucking up.
[1]: http://www.passmark.com/forum/memtest86/5395-rowhammer-mitig...
fork(2) does COW. With careful design† forking a new process only results in new and modified pages being not shared.
† Hard! But single-process threads + security is hard too.
http://unix.stackexchange.com/questions/58145/how-does-copy-...
Just wanted to point out that memory usage isn't necessarily inherent to multiprocess, but with a sizable portion of users on Windows the point is practically moot anyway.
As for security, no, unless there's some unknown vulnerability now (or that they create), that will be ported over and somehow more effective between (potential) processes. So, I doubt it.