Re: [PATCH v4] kconfig: add kconfig-sym-check static checker

[Julian Braha <julianbraha@gmail.com>]

On 6/24/26 04:34, Sergey Senozhatsky wrote:
> OK, maybe they are not similar, as Julian pointed out.  Makes
> we wonder is there any benefit in moving this functionality
> into kconfig (which is the tool that deals with Kconfig files).

Agreed, it would be ideal if the check could be part of the kconfig
interpeter.

However...

Linux does a funky thing with its architecture handling in kconfig:
it looks up the architecture from a makefile variable and uses that to
resolve a kconfig file import in 'arch/Kconfig'.

This means e.g. when evaluating the kconfig on an x86 machine, all of
the config options in the RISC-V kconfig are never reached, thus never
parsed, and never added to the symbol table. As far as the interpeter is
aware, any reference to, say, RISCV_SBI is a dead reference on x86.

Yet, options throughout the kernel can reference arch-specific options.
Try searching in menuconfig for the RISCV-only option HVC_RISCV_SBI on
x86, and you'll successfully find it, because it's defined in 'drivers/'
(not downstream of arch/Kconfig). Then try searching for its dependency,
RISCV_SBI. Apparently it doesn't exist? In my opinion, this should also
be considered a bug in the frontend...

All this is to say, until architectures are restructured in kconfig,
alarming on unknown options would output 99% noise.

- Julian Braha