Re: [RFC PATCH 00/21] KCFI support

Sami Tolvanen
2022-05-04T20:19:29Z

On Wed, May 4, 2022 at 9:41 AM Sami Tolvanen <samitolvanen@google.com> wrote:
>
> Hi Mark,
>
> On Wed, May 4, 2022 at 9:18 AM Mark Rutland <mark.rutland@arm.com> wrote:
> > I wanted to give this a spin on arm64, but I'm seeing some very odd toolchain
> > behaviour. I'm not sure if I've done something wrong, or if I'm just hitting an
> > edge-case, but it looks like using -fsanitize=kcfi causes the toolchain to hit
> > out-of-memory errors and other issues which look like they could be memory
> > corruption.
>
> Thanks for the detailed bug report! It definitely looks like something
> is wrong with the recent switch from std::string to Twine in the Clang
> code. I didn't see this issue when compiling the arm64 kernel, but
> I'll take a closer look and see if I can reproduce it.

I was able to reproduce this by turning off assertions in Clang. It
seems to work fine with -DLLVM_ENABLE_ASSERTIONS=ON. I'll go fix.

Sami