Re: [PATCH] ARM: Do not select HAVE_RUST when KASAN is enabled

[Nathan Chancellor <nathan@kernel.org>]

On Mon, May 11, 2026 at 08:21:48AM +0000, Alice Ryhl wrote:
> On Mon, May 11, 2026 at 05:02:44PM +0900, Nathan Chancellor wrote:
> > When KASAN is enabled, such as with allmodconfig, the build fails when
> > building the Rust code with:
> > 
> >   error: kernel-address sanitizer is not supported for this target
> > 
> >   error: aborting due to 1 previous error
> > 
> >   make[4]: *** [rust/Makefile:654: rust/core.o] Error 1
> > 
> > The arm-unknown-linux-gnueabi target does not support KASAN, so avoid
> > saying Rust is supported when it is enabled.
> > 
> > Cc: stable@vger.kernel.org
> > Fixes: ccb8ce526807 ("ARM: 9441/1: rust: Enable Rust support for ARMv7")
> > Link: https://github.com/Rust-for-Linux/linux/issues/1234
> > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> 
> I would probably suggest moving the conditions out to a separate
> RUSTC_SUPPORTS_ARM config option similar to what I did in commit
> d077242d68a3 ("rust: support for shadow call stack sanitizer").
> 
> This way it will be simpler to adjust this logic when the target obtains
> support for this sanitizer.

Sure, I kept it simple for backporting purposes but I don't mind
breaking out the dependencies into their own symbol, even though it
feels like that could be done when support for the sanitizer is
re-enabled, which would truly mirror what you did. No strong opinion
though, so I will send a v2 after giving some time for other comments.

> Also, we may need the same change for CONFIG_CFI too.

I think the dependencies of HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC
prevent RUST from being selected when CFI is enabled for ARM, so I don't
think there is a problem there.

-- 
Cheers,
Nathan