Re: [PATCH] objtool/rust: add one more `noreturn` Rust function

["Gary Guo" <gary@garyguo.net>]

On Sat Aug 15, 2026 at 3:55 PM BST, Miguel Ojeda wrote:
> On Wed, Aug 5, 2026 at 4:45 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>>
>> When the pointer formatting series [1] is applied and KUnit tests
>> are enabled, `objtool` would report an error with any of our
>> supported Rust versions. For instance, with Rust 1.97.1:
>
> With the version that I applied of that series, this was not strictly
> needed anymore.

I am seeing this function causing issue on my 1.85.1 -Os build, although the
error message is different this time:

rust/kernel.o: warning: objtool: _RNvXs2_NtNtCsaNryh1j6xD7_4core3str6traitseINtNtNtB9_3ops5index5IndexINtNtBJ_5range9RangeFromjEE5indexCsldbe0TGTmNx_6kernel+0x1d: stack state mismatch: cfa1=4+8 cfa2=4+16

Disassembly shows that the function call before the warning location is a call
to _4core3str16slice_error_fail, and objtool thought it can return (which will
end up with a unbalanced stack if it does return).

Applying the patch fixes the issue.

Best,
Gary