[PATCH] riscv: hwprobe: avoid uninitialized variable use in hwprobe_arch_id()

[Evan Green]

On Sat, Oct 18, 2025 at 8:32 AM Paul Walmsley <pjw at kernel.org> wrote:
>
> Resolve this smatch warning:
>
>   arch/riscv/kernel/sys_hwprobe.c:50 hwprobe_arch_id() error: uninitialized symbol 'cpu_id'.
>
> This could happen if hwprobe_arch_id() was called with a key ID of
> something other than MVENDORID, MIMPID, and MARCHID.  This does not
> happen in the current codebase.  The only caller of hwprobe_arch_id()
> is a function that only passes one of those three key IDs.
>
> For the sake of reducing static analyzer warning noise, and in the
> unlikely event that hwprobe_arch_id() is someday called with some
> other key ID, validate hwprobe_arch_id()'s input to ensure that
> 'cpu_id' is always initialized before use.
>
> Fixes: ea3de9ce8aa280 ("RISC-V: Add a syscall for HW probing")
> Cc: Evan Green <evan at rivosinc.com>
> Signed-off-by: Paul Walmsley <pjw at kernel.org>

Reviewed-by: Evan Green <evan at rivosinc.com>