> From: Andy Lutomirski <luto@xxxxxxxxxx> > I think this is very clever, but I find myself wondering what happens if people > start trying to abuse this by, for example, setting up a remote mapping > pointing to fun regions like userfaultfd or another remote mapping. Can ptrace() be used to abuse fun regions of a process address space? Remote mapping recursiveness can be eliminated by checking the VMA the remote page is extracted from. (NYI) > I'm a little concerned that it's actually too clever and that maybe a more > straightforward solution should be investigated. I personally rather dislike > the KVM model in which the guest address space mirrors the host (QEMU) > address space rather than being its own thing. I've seen a few internal mmap()s throughout the kernel. Just wondering how memory accounting is implemented for these cases. Will this be reflected in the memory usage of the process that controls such a module? Especially in the case of a virtual machine that needs a few GBs of memory. Mircea
