[PATCH v3 0/4] Rust KASAN Support

[Matthew Maurer <mmaurer@google.com>]

Right now, if we turn on KASAN, Rust code will cause violations because
it's not enabled properly.

This series:
1. Adds flag probe macros for Rust - now that we're setting a minimum rustc
   version instead of an exact one, these could be useful in general. We need
   them in this patch because we don't set a restriction on which LLVM rustc
   is using, which is what KASAN actually cares about.
2. Makes `rustc` enable the relevant KASAN sanitizer flags when C does.
3. Adds a smoke test to the `kasan_test` KUnit suite to check basic
   integration.

This patch series requires the target.json array support patch [1] as
the x86_64 target.json file currently produced does not mark itself as KASAN
capable, and is rebased on top of the KASAN Makefile rewrite [2].

Differences from v2 [3]:
1. Rebased on top of the maintainer's cleanup of the Makefile.
2. Cleaned up the UaF test based on feedback.
3. Calls out that KASAN_SW_TAGS is not yet supported in the config.

The notable piece of feedback I have not followed is in the renaming of
kasan_test.c to kasan_test_c.c - this was done in order to allow the
module to be named kasan_test but consist of two .o files. The other
options I see are renaming the test suite or creating a separate Rust
test suite, but both of those seemed more invasive than the rename. Let
me know if you have another approach you'd prefer there.

[1] https://lore.kernel.org/lkml/20240730-target-json-arrays-v1-1-2b376fd0ecf4@google.com/
[2] https://lore.kernel.org/all/20240813224027.84503-1-andrey.konovalov@linux.dev
[3] https://lore.kernel.org/all/20240812232910.2026387-1-mmaurer@google.com/


Matthew Maurer (4):
  kbuild: rust: Define probing macros for rustc
  kbuild: rust: Enable KASAN support
  rust: kasan: Rust does not support KHWASAN
  kasan: rust: Add KASAN smoke test via UAF

 init/Kconfig                              |  1 +
 mm/kasan/Makefile                         |  9 +++-
 mm/kasan/kasan.h                          |  1 +
 mm/kasan/{kasan_test.c => kasan_test_c.c} | 11 +++++
 mm/kasan/kasan_test_rust.rs               | 19 ++++++++
 scripts/Kconfig.include                   |  8 ++++
 scripts/Makefile.compiler                 | 15 +++++++
 scripts/Makefile.kasan                    | 54 ++++++++++++++++-------
 scripts/Makefile.lib                      |  3 ++
 scripts/generate_rust_target.rs           |  1 +
 10 files changed, 105 insertions(+), 17 deletions(-)
 rename mm/kasan/{kasan_test.c => kasan_test_c.c} (99%)
 create mode 100644 mm/kasan/kasan_test_rust.rs

-- 
2.46.0.184.g6999bdac58-goog