This adds support for Software Tag-Based KASAN (KASAN_SW_TAGS) when
CONFIG_RUST is enabled. This requires that rustc includes support for
the kernel-hwaddress sanitizer, which is available since 1.96.0 [1].

Link: https://github.com/rust-lang/rust/pull/153049 [1]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 init/Kconfig           | 2 +-
 scripts/Makefile.kasan | 2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 444ce811ea67..545cbe889a52 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2179,7 +2179,7 @@ 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_SW_TAGS
+	depends on !KASAN_SW_TAGS || RUSTC_VERSION >= 109600
 	depends on !(MITIGATION_RETHUNK && KASAN) || RUSTC_VERSION >= 108300
 	help
 	  Enables Rust support in the kernel.
diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index 9a9033096c88..3833e0b3b857 100644
--- a/scripts/Makefile.kasan
+++ b/scripts/Makefile.kasan
@@ -70,8 +70,6 @@ ifdef CONFIG_KASAN_SW_TAGS
 
 CFLAGS_KASAN := -fsanitize=kernel-hwaddress
 
-# This sets flags that will enable SW_TAGS KASAN once enabled in Rust. These
-# will not work today, and is guarded against in dependencies for CONFIG_RUST.
 RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress
 
 ifdef CONFIG_KASAN_INLINE

-- 
2.53.0.1018.g2bb0e51243-goog

On 3/25/26 10:26 AM, Alice Ryhl wrote:
> This adds support for Software Tag-Based KASAN (KASAN_SW_TAGS) when
> CONFIG_RUST is enabled. This requires that rustc includes support for
> the kernel-hwaddress sanitizer, which is available since 1.96.0 [1].
> 
> Link: https://github.com/rust-lang/rust/pull/153049 [1]
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>

Reviewed-by: Danilo Krummrich <dakr@kernel.org>