Re: [PATCH] menuconfig: fix NULL pointer dereference when searchinga symbol

From: Libo Chen
Date: Mon May 06 2013 - 22:49:44 EST


On 2013/5/7 10:40, Li Zefan wrote:
> Searching PPC_EFIKA results segmentation fault, and it's because
> get_symbol_prop() returns NULL.
>
> In this case CONFIG_PPC_EFIKA is defined in arch/powerpc/platforms/
> 52xx/Kconfig, so it won't be parsed if ARCH!=PPC, but menuconfig
> knows this symbol when it parses sound/soc/fsl/Kconfig:
>
> config SND_MPC52xx_SOC_EFIKA
> tristate "SoC AC97 Audio support for bbplan Efika and STAC9766"
> depends on PPC_EFIKA
>
> This bug was introduced by commit bcdedcc1afd6 ("menuconfig: print more
> info for symbol without prompts").


It works!

Tested-by: Libo Chen <libo.chen@xxxxxxxxxx>

>
> Reported-by: Borislav Petkov <bp@xxxxxxxxx>
> Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
> ---
> scripts/kconfig/menu.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
> index 826da66..b5c7d90 100644
> --- a/scripts/kconfig/menu.c
> +++ b/scripts/kconfig/menu.c
> @@ -600,14 +600,18 @@ void get_symbol_str(struct gstr *r, struct symbol *sym,
> }
> for_all_prompts(sym, prop)
> get_prompt_str(r, prop, head);
> +
> prop = get_symbol_prop(sym);
> - str_printf(r, _(" Defined at %s:%d\n"), prop->menu->file->name,
> - prop->menu->lineno);
> - if (!expr_is_yes(prop->visible.expr)) {
> - str_append(r, _(" Depends on: "));
> - expr_gstr_print(prop->visible.expr, r);
> - str_append(r, "\n");
> + if (prop) {
> + str_printf(r, _(" Defined at %s:%d\n"), prop->menu->file->name,
> + prop->menu->lineno);
> + if (!expr_is_yes(prop->visible.expr)) {
> + str_append(r, _(" Depends on: "));
> + expr_gstr_print(prop->visible.expr, r);
> + str_append(r, "\n");
> + }
> }
> +
> hit = false;
> for_all_properties(sym, prop, P_SELECT) {
> if (!hit) {
>


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