rust: kasan: KASAN+RUST requires clang

[ Upstream commit 5b27154 ]

Kernel KASAN involves passing various llvm/gcc specific arguments to
the C and Rust compiler. Since these arguments differ between llvm and
gcc, it's not safe to mix an llvm-based rustc with a gcc build when
kasan is enabled.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Cc: stable@vger.kernel.org
Fixes: e311740 ("kbuild: rust: Enable KASAN support")
Link: https://patch.msgid.link/20260408-kasan-rust-sw-tags-v3-1-e07964d14363@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Darksonn

init/Kconfig

@@ -2096,6 +2096,7 @@ config RUST
 	depends on !CFI || HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
 	select CFI_ICALL_NORMALIZE_INTEGERS if CFI
 	depends on !CALL_PADDING || RUSTC_VERSION >= 108100
+	depends on !KASAN || CC_IS_CLANG
 	depends on !KASAN_SW_TAGS
 	depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300
 	help