Re: [PATCH v3 2/4] vhost-vdpa: introduce STOP backend feature bit

[Dan Carpenter]

On Fri, May 27, 2022 at 10:36:55AM +0300, Dan Carpenter wrote:
> static void match_pointer(struct expression *ret_value)
> {
>         struct symbol *type;
>         char *name;
> 
>         type = cur_func_return_type();
>         if (!type || sval_type_max(type).value != 1)
>                 return;
> 
>         if (!is_pointer(ret_value))
>                 return;
> 
>         name = expr_to_str(ret_value);
>         sm_msg("'%s' return pointer cast to bool", name);
>         free_string(name);
> }

I found a bug in Smatch with this check.  With the Smatch bug fixed then
there is only only place which does a legitimate implied pointer to bool
cast.  A different function returns NULL on error instead of false.

drivers/gpu/drm/i915/display/intel_dmc.c:249 intel_dmc_has_payload() 'i915->dmc.dmc_info[0]->payload' return pointer cast to bool
drivers/net/wireless/rndis_wlan.c:1980 rndis_bss_info_update() '(0)' return pointer cast to bool
drivers/net/wireless/rndis_wlan.c:1989 rndis_bss_info_update() '(0)' return pointer cast to bool
drivers/net/wireless/rndis_wlan.c:1995 rndis_bss_info_update() '(0)' return pointer cast to bool

regards,
dan carpenter