On Thu, Oct 10, 2024 at 09:38:27AM +0000, Alice Ryhl wrote: > The HAVE_CFI_ICALL_NORMALIZE_INTEGERS option has some tricky conditions > when KASAN or GCOV are turned on, as in that case we need some clang and > rustc fixes [1][2] to avoid boot failures. The intent with the current > setup is that you should be able to override the check and turn on the > option if your clang/rustc has the fix. However, this override does not > work in practice. Thus, use the new RUSTC_LLVM_VERSION to correctly > implement the check for whether the fix is available. > > Additionally, remove KASAN_HW_TAGS from the list of incompatible > options. The CFI_ICALL_NORMALIZE_INTEGERS option is incompatible with > KASAN because LLVM will emit some constructors when using KASAN that are > assigned incorrect CFI tags. These constructors are emitted due to use > of -fsanitize=kernel-address or -fsanitize=kernel-hwaddress that are > respectively passed when KASAN_GENERIC or KASAN_SW_TAGS are enabled. > However, the KASAN_HW_TAGS option relies on hardware support for MTE > instead and does not pass either flag. (Note also that KASAN_HW_TAGS > does not `select CONSTRUCTORS`.) > > Link: https://github.com/llvm/llvm-project/pull/104826 [1] > Link: https://github.com/rust-lang/rust/pull/129373 [2] > Fixes: 4c66f8307ac0 ("cfi: encode cfi normalized integers + kasan/gcov bug in Kconfig") > Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> This looks correct to me. Checking the LLVM version is definitely a better option. Thanks! Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Sami
