Re: [bug report] ASoC: SOF: avoid a NULL dereference with unsupported widgets

["Péter Ujfalusi" <peter.ujfalusi@linux.intel.com>]

Hi Dan,

On 31/03/2023 09:58, Dan Carpenter wrote:
> Hello Guennadi Liakhovetski,
> 
> This is a semi-automatic email about new static checker warnings.
> 
> The patch e3720f92e023: "ASoC: SOF: avoid a NULL dereference with 
> unsupported widgets" from Mar 29, 2023, leads to the following Smatch 
> complaint:
> 
> sound/soc/sof/ipc4-topology.c:2353 sof_ipc4_route_setup()
> error: we previously assumed 'sink_fw_module' could be null (see line 2351)
> 
> sound/soc/sof/ipc4-topology.c:2353 sof_ipc4_route_setup()
> error: we previously assumed 'src_fw_module' could be null (see line 2351)
> 
> sound/soc/sof/ipc4-topology.c
>   2350	
>   2351		if (!src_fw_module || !sink_fw_module) {
>                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> One of these is NULL.
> 
>   2352			/* The NULL module will print as "(efault)" */
>   2353			dev_err(sdev->dev, "source %s or sink %s widget weren't set up properly\n",
>   2354				src_fw_module->man4_module_entry.name,
>   2355				sink_fw_module->man4_module_entry.name);
>                                 ^^^^^^^^^^^^^^
> Both are dereferenced.  The comment is very puzzling.

if src_fw_module is NULL then the print will be:
source (efault) or sink sink.module.name widget weren't set up properly

Guennadi is relying on some black magic in the printk system to handle
the printing instead of open coding.

-- 
Péter