[PATCH] D36587: Add NetBSD ASAN shadow mapping for x86-64

[Kamil Rytarowski via Phabricator via llvm-commits]

krytarowski added a comment.

I've checked that ShadowOffset 0 breaks ASAN.

In https://reviews.llvm.org/D36587#854807, @eugenis wrote:

> Looking at the comment,
>  0000 0000 1000 - 0080 0000 0000: main binary and/or MAP_32BIT mappings (512GB)
>  5500 0000 0000 - 5680 0000 0000: pie binaries without ASLR or on 4.1+ kernels
>  7e80 0000 0000 - 8000 0000 0000: modules and main thread stack
>
> ^ these are the OS constraints, the rest can be moved.


I'm having now trouble to translate these values to NetBSD.

> Another constraint is MemToShadowImpl() which, for any address in, I assume, writable memory (so any of the above + heap) needs to provide an distinct address in "shadow". AFAIK, "metainfo" and "traces" are completely arbitrary.

Another thread: If I understand correctly there is an assumption that PIE code is mapped on Linux/FreeBSD into adjacent memory regions. This is not true on NetBSD (@joerg can correct me).

I was trying to reuse Linux/FreeBSD process memory mapping and all tests fail. It breaks at PIE detection (I disabled it locally to check what happens).


Repository:
  rL LLVM

https://reviews.llvm.org/D36587