Re: [PATCH] fix: drm/vmwgfx: vmw_user_shader_alloc: fix base object refcount leak on ttm_base_object_init failure

Hi WenTao,

kernel test robot noticed the following build errors:

[auto build test ERROR on drm-misc/drm-misc-next]
[also build test ERROR on daeinki-drm-exynos/exynos-drm-next drm/drm-next drm-i915/for-linux-next drm-i915/for-linux-next-fixes drm-tip/drm-tip linus/master v7.2-rc6 next-20260806]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/WenTao-Liang/fix-drm-vmwgfx-vmw_user_shader_alloc-fix-base-object-refcount-leak-on-ttm_base_object_init-failure/20260807-080356
base:   https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next
patch link:    https://lore.kernel.org/r/20260626150142.49732-1-vulab%40iscas.ac.cn
patch subject: [PATCH] fix: drm/vmwgfx: vmw_user_shader_alloc: fix base object refcount leak on ttm_base_object_init failure
config: i386-allmodconfig (https://download.01.org/0day-ci/archive/20260808/[email protected]/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260808/[email protected]/reproduce)

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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All errors (new ones prefixed by >>):

   drivers/gpu/drm/vmwgfx/vmwgfx_shader.c: In function 'vmw_user_shader_alloc':
>> drivers/gpu/drm/vmwgfx/vmwgfx_shader.c:727:39: error: passing argument 1 of 'ttm_base_object_unref' from incompatible pointer type [-Wincompatible-pointer-types]
     727 |                 ttm_base_object_unref(&ushader->base);
         |                                       ^~~~~~~~~~~~~~
         |                                       |
         |                                       struct ttm_base_object *
   In file included from drivers/gpu/drm/vmwgfx/vmwgfx_drv.h:27,
                    from drivers/gpu/drm/vmwgfx/vmwgfx_shader.c:32:
   drivers/gpu/drm/vmwgfx/ttm_object.h:192:60: note: expected 'struct ttm_base_object **' but argument is of type 'struct ttm_base_object *'
     192 | extern void ttm_base_object_unref(struct ttm_base_object **p_base);
         |                                   ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~


vim +/ttm_base_object_unref +727 drivers/gpu/drm/vmwgfx/vmwgfx_shader.c

   684	
   685	static int vmw_user_shader_alloc(struct vmw_private *dev_priv,
   686					 struct vmw_bo *buffer,
   687					 size_t shader_size,
   688					 size_t offset,
   689					 SVGA3dShaderType shader_type,
   690					 uint8_t num_input_sig,
   691					 uint8_t num_output_sig,
   692					 struct ttm_object_file *tfile,
   693					 u32 *handle)
   694	{
   695		struct vmw_user_shader *ushader;
   696		struct vmw_resource *res, *tmp;
   697		int ret;
   698	
   699		ushader = kzalloc_obj(*ushader);
   700		if (unlikely(!ushader)) {
   701			ret = -ENOMEM;
   702			goto out;
   703		}
   704	
   705		res = &ushader->shader.res;
   706		ushader->base.shareable = false;
   707		ushader->base.tfile = NULL;
   708	
   709		/*
   710		 * From here on, the destructor takes over resource freeing.
   711		 */
   712	
   713		ret = vmw_gb_shader_init(dev_priv, res, shader_size,
   714					 offset, shader_type, num_input_sig,
   715					 num_output_sig, buffer,
   716					 vmw_user_shader_free);
   717		if (unlikely(ret != 0))
   718			goto out;
   719	
   720		tmp = vmw_resource_reference(res);
   721		ret = ttm_base_object_init(tfile, &ushader->base, false,
   722					   VMW_RES_SHADER,
   723					   &vmw_user_shader_base_release);
   724	
   725		if (unlikely(ret != 0)) {
   726			vmw_resource_unreference(&tmp);
 > 727			ttm_base_object_unref(&ushader->base);
   728			goto out_err;
   729		}
   730	
   731		if (handle)
   732			*handle = ushader->base.handle;
   733	out_err:
   734		vmw_resource_unreference(&res);
   735	out:
   736		return ret;
   737	}
   738	

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