Re: [linux-next:master 8752/11953] sound/soc/codecs/lpass-macro-common.c:53 lpass_macro_pds_init() warn: passing zero to 'ERR_PTR'

[Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>]

On 3/11/2022 5:23 PM, Dan Carpenter wrote:
Thanks for Your time and valuable inputs Dan!!
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   71941773e143369a73c9c4a3b62fbb60736a1182
> commit: 9e3d83c52844f955aa2975f78cee48bf9f72f5e1 [8752/11953] ASoC: codecs: Add power domains support in digital macro codecs
> config: arm-randconfig-m031-20220310 (https://download.01.org/0day-ci/archive/20220311/202203111754.32TAMFKD-lkp@intel.com/config)
> compiler: arm-linux-gnueabi-gcc (GCC) 11.2.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> smatch warnings:
> sound/soc/codecs/lpass-macro-common.c:53 lpass_macro_pds_init() warn: passing zero to 'ERR_PTR'
>
> vim +/ERR_PTR +53 sound/soc/codecs/lpass-macro-common.c
>
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  14  struct lpass_macro *lpass_macro_pds_init(struct device *dev)
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  15  {
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  16  	struct lpass_macro *l_pds;
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  17  	int ret;
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  18
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  19  	if (!of_find_property(dev->of_node, "power-domains", NULL))
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  20  		return NULL;
>
> Returning NULL here will lead to a crash in tx_macro_runtime_resume()
>
> When a function returns a mix of NULL and error pointers, then NULL
> means the feature is deliberately disabled.  It's not an error, it's a
> deliberate choice by the distro or sys admin.  The caller has to
> be written to allow the feature to be disabled.
>
> An example of this might be LEDs.  Maybe people don't want LEDs so code
> has to asume that the led->ops pointer might be NULL and check for that
> before dereferencing it.

Actually, it's optional here. For some targets, with lpass ADSP enabled, 
power domains are not required.

So is the reason, returning NULL Here.

>
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  21
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  22  	l_pds = devm_kzalloc(dev, sizeof(*l_pds), GFP_KERNEL);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  23  	if (!l_pds)
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  24  		return ERR_PTR(-ENOMEM);
>
> Good.
>
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  25
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  26  	l_pds->macro_pd = dev_pm_domain_attach_by_name(dev, "macro");
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  27  	if (IS_ERR_OR_NULL(l_pds->macro_pd))
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  28  		return NULL;
>
> If this feature is optional then it should be:
>
> 	if (IS_ERR_OR_NULL(l_pds->macro_pd))
> 		return ERR_CAST(l_pds->macro_pd);
>
> The admin deliberately chose to enable the feature so we can't just
> ignore errors and convert them to NULL.

Here it's not optional, if power domains feature is available then macro 
and dcodec power domains should be present.

So will update it like below.

	if (IS_ERR_OR_NULL(l_pds->macro_pd)) {
		ret = PTR_ERR(l_pds->macro_pd);
		goto macro_err;
	}

>
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  29
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  30  	ret = pm_runtime_get_sync(l_pds->macro_pd);
>
> This is correct, but the documentation for pm_runtime_get_sync() says to
> consider pm_runtime_resume_and_get() instead.  The error handling is
> slightly different and easier.  I forget the details.
Okay. Will update accordingly.
>
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  31  	if (ret < 0) {
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  32  		pm_runtime_put_noidle(l_pds->macro_pd);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  33  		goto macro_err;
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  34  	}
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  35
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  36  	l_pds->dcodec_pd = dev_pm_domain_attach_by_name(dev, "dcodec");
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  37  	if (IS_ERR_OR_NULL(l_pds->dcodec_pd))
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  38  		goto dcodec_err;
>
> Again this IS_ERR_OR_NULL() check needs to preserve the error codes:
>
> 	if (IS_ERR_OR_NULL(l_pds->dcodec_pd)) {
> 		ret = PTR_ERR(l_pds->dcodec_pd);
> 		goto dcodec_err;
> 	}
Okay. Will update accordingly.
>
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  39
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  40  	ret = pm_runtime_get_sync(l_pds->dcodec_pd);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  41  	if (ret < 0) {
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  42  		pm_runtime_put_noidle(l_pds->dcodec_pd);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  43  		goto dcodec_sync_err;
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  44  	}
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  45  	return l_pds;
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  46
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  47  dcodec_sync_err:
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  48  	dev_pm_domain_detach(l_pds->dcodec_pd, false);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  49  dcodec_err:
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  50  	pm_runtime_put(l_pds->macro_pd);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  51  macro_err:
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  52  	dev_pm_domain_detach(l_pds->macro_pd, false);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26 @53  	return ERR_PTR(ret);
> 9e3d83c52844f95 Srinivasa Rao Mandadapu 2022-02-26  54  }
>
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