linux-kernel - Re: [PATCH] drm: gud: replace WARN_ON/WARN_ON

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Message-ID: <b87337baa6bdb69354f368a5526a68f1cc5f701c.camel@aol.com>
Date: Mon, 22 Sep 2025 14:07:22 +0100
From: Ruben Wauters <rubenru09@....com>
To: Dan Carpenter <dan.carpenter@...aro.org>, oe-kbuild@...ts.linux.dev, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard
 <mripard@...nel.org>, Thomas Zimmermann	 <tzimmermann@...e.de>, David
 Airlie <airlied@...il.com>, Simona Vetter	 <simona@...ll.ch>
Cc: lkp@...el.com, oe-kbuild-all@...ts.linux.dev, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm: gud: replace WARN_ON/WARN_ON_ONCE with drm versions

On Mon, 2025-09-22 at 08:47 +0300, Dan Carpenter wrote:
> Hi Ruben,
> 
> kernel test robot noticed the following build warnings:
> 
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:   
> https://github.com/intel-lab-lkp/linux/commits/Ruben-Wauters/drm-gud-replace-WARN_ON-WARN_ON_ONCE-with-drm-versions/20250914-235627
> base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
> patch link:   
> https://lore.kernel.org/r/20250914155308.2144-1-rubenru09%40aol.com
> patch subject: [PATCH] drm: gud: replace WARN_ON/WARN_ON_ONCE with
> drm versions
> config: x86_64-randconfig-161-20250921
> (https://download.01.org/0day-ci/archive/20250921/202509212215.c8v3RK
> mL-lkp@...el.com/config)
> compiler: clang version 20.1.8
> (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b5
> 05e9c7261)

Hi,

Thank you for catching this, I completely missed it. Since the patch
has already been applied to drm-misc-next I will send another patch to
fix this issue.

> If you fix the issue in a separate patch/commit (i.e. not just a new
> version of
> the same patch/commit), kindly add following tags
> > Reported-by: kernel test robot <lkp@...el.com>
> > Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> > Closes:
> > https://lore.kernel.org/r/202509212215.c8v3RKmL-lkp@intel.com/
> 
> smatch warnings:
> drivers/gpu/drm/gud/gud_connector.c:597
> gud_connector_fill_properties() warn: passing a valid pointer to
> 'PTR_ERR'
> 
> vim +/PTR_ERR +597 drivers/gpu/drm/gud/gud_connector.c
> 
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  580  int
> gud_connector_fill_properties(struct drm_connector_state
> *connector_state,
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13 
> 581  				  struct gud_property_req *properties)
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  582  {
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  583  	struct gud_connector
> *gconn = to_gud_connector(connector_state->connector);
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  584  	unsigned int i;
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  585  
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  586  	for (i = 0; i <
> gconn->num_properties; i++) {
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  587  		u16 prop =
> gconn->properties[i];
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  588  		u64 val;
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  589  
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  590  		if (prop ==
> GUD_PROPERTY_BACKLIGHT_BRIGHTNESS) {
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  591  			val
> = connector_state->tv.brightness;
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  592  		} else {
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13 
> 593  			unsigned int *state_val;
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  594  
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13 
> 595  			state_val = gud_connector_tv_state_val(prop, &connector_state->tv);
> d00e57106c0d0c Ruben Wauters  2025-09-14  596  			if
> (drm_WARN_ON_ONCE(connector_state->connector->dev, state_val))
> 
> You accidentally deleted the IS_ERR() check so now this function is
> badly broken.

What I think happened was that on replacing WARN_ON_ONCE with
drm_WARN_ON_ONCE I had to find a drm device for the first parameter.
Since there was not one readily available I believe I ended up re-
writing this line, and accidentally left out the IS_ERR(). I will fix
this.

> 	if (drm_WARN_ON_ONCE(connector_state->connector->dev,
> IS_ERR(state_val)))
> 
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13
> @597  				return PTR_ERR(state_val);
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  598  
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  599  			val
> = *state_val;
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  600  		}
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  601  
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13 
> 602  		properties[i].prop = cpu_to_le16(prop);
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13 
> 603  		properties[i].val = cpu_to_le64(val);
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  604  	}
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  605  
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  606  	return gconn-
> >num_properties;
> 40e1a70b4aedf2 Noralf Trønnes 2021-03-13  607  }

Thank you for reporting this

Ruben Wauters