Re: [PATCH] kconfig: check for a NULL pointer before access

[Randy Dunlap <rdunlap@infradead.org>]

Hi,

On 5/22/25 5:07 PM, Bill Wendling wrote:
> The call to 'prop_get_symbol' may return NULL in some cases. The if-then
> statement accesses the returned value without checking if it's
> non-NULL. After inlining, the compiler may treat the conditional as
> 'undefined behavior', which the compiler may take the opportunity to do
> whatever it wants with the UB path. This patch simply adds a check to
> ensure that 'def_sym' is non-NULL to avoid this behavior.
> 
> Signed-off-by: Bill Wendling <morbo@google.com>
> ---
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: linux-kbuild@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  scripts/kconfig/symbol.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
> index d57f8cbba291..9c5068225328 100644
> --- a/scripts/kconfig/symbol.c
> +++ b/scripts/kconfig/symbol.c
> @@ -272,7 +272,7 @@ struct symbol *sym_choice_default(struct menu *choice)
>   if (prop->visible.tri == no)
>   continue;
>   def_sym = prop_get_symbol(prop);
> - if (def_sym->visible != no)
> + if (def_sym && def_sym->visible != no)
>   return def_sym;
>   }
> 

The patch is missing the source file's indentation.
(spaces/tabs are lost)

-- 
~Randy