[compiler-rt] [win/asan] Don't intercept memset etc. in ntdll (PR #120397)

[Zack Johnson via llvm-commits]

zacklj89 wrote:

@mstorsjo just adding some comments here to help with the conversation.

> I did try adding msvcrt.dll to this list, but that doesn't seem to fix the issue entirely either - I'm ending up with errors like this instead:
> ==5236==ERROR: AddressSanitizer: attempting to call malloc_usable_size() for pointer which is not owned:

Presumably this is happening as a result of calls to `_Crt*` APIs or msvcrt initialization routines that are dealing with memory that ASan is not aware of that end up making calls to intercepted APIs?

> Reinstate intercepting ntdll.dll, if building for mingw + msvcrt.dll. While it isn't the entirely right thing to do, we should reach the same level of functionality as before

Perhaps there should be a runtime option (defaulting off) that allows this, as if I remember correctly Mozilla was having both reentrancy and performance issues as a result of this. FWIW, MSVC behaves very similarly to #120110.



https://github.com/llvm/llvm-project/pull/120397