Re: [drm-misc:for-linux-next 2/2] drivers/gpu/drm/drm_debugfs.c:212:33: sparse: sparse: non size-preserving pointer to integer cast

[Boris Brezillon <boris.brezillon@collabora.com>]

On Fri, 21 Jul 2023 02:06:16 +0800
kernel test robot <lkp@intel.com> wrote:

> tree:   git://anongit.freedesktop.org/drm/drm-misc for-linux-next
> head:   c7a472297169156252a50d76965eb36b081186e2
> commit: 4f66feeab173bd73e71028b8c2e1dcea07e32dd5 [2/2] drm: debugfs: provide infrastructure to dump a DRM GPU VA space
> config: i386-randconfig-r092-20230720 (https://download.01.org/0day-ci/archive/20230721/202307210230.t2OnM5g0-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce: (https://download.01.org/0day-ci/archive/20230721/202307210230.t2OnM5g0-lkp@intel.com/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 <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202307210230.t2OnM5g0-lkp@intel.com/
> 
> sparse warnings: (new ones prefixed by >>)
> >> drivers/gpu/drm/drm_debugfs.c:212:33: sparse: sparse: non size-preserving pointer to integer cast  
> 
> vim +212 drivers/gpu/drm/drm_debugfs.c
> 
>    178	
>    179	/**
>    180	 * drm_debugfs_gpuva_info - dump the given DRM GPU VA space
>    181	 * @m: pointer to the &seq_file to write
>    182	 * @mgr: the &drm_gpuva_manager representing the GPU VA space
>    183	 *
>    184	 * Dumps the GPU VA mappings of a given DRM GPU VA manager.
>    185	 *
>    186	 * For each DRM GPU VA space drivers should call this function from their
>    187	 * &drm_info_list's show callback.
>    188	 *
>    189	 * Returns: 0 on success, -ENODEV if the &mgr is not initialized
>    190	 */
>    191	int drm_debugfs_gpuva_info(struct seq_file *m,
>    192				   struct drm_gpuva_manager *mgr)
>    193	{
>    194		struct drm_gpuva *va, *kva = &mgr->kernel_alloc_node;
>    195	
>    196		if (!mgr->name)
>    197			return -ENODEV;
>    198	
>    199		seq_printf(m, "DRM GPU VA space (%s) [0x%016llx;0x%016llx]\n",
>    200			   mgr->name, mgr->mm_start, mgr->mm_start + mgr->mm_range);
>    201		seq_printf(m, "Kernel reserved node [0x%016llx;0x%016llx]\n",
>    202			   kva->va.addr, kva->va.addr + kva->va.range);
>    203		seq_puts(m, "\n");
>    204		seq_puts(m, " VAs | start              | range              | end                | object             | object offset\n");
>    205		seq_puts(m, "-------------------------------------------------------------------------------------------------------------\n");
>    206		drm_gpuva_for_each_va(va, mgr) {
>    207			if (unlikely(va == kva))
>    208				continue;
>    209	
>    210			seq_printf(m, "     | 0x%016llx | 0x%016llx | 0x%016llx | 0x%016llx | 0x%016llx\n",
>    211				   va->va.addr, va->va.range, va->va.addr + va->va.range,
>  > 212				   (u64)va->gem.obj, va->gem.offset);  

Oops, I didn't notice it when reviewing. You're leaking a kernel address
to user space here. You should probably use %p to print the GEM object
address, and add `no_hash_pointers` to your cmdline when you want to
debug things.

>    213		}
>    214	
>    215		return 0;
>    216	}
>    217	EXPORT_SYMBOL(drm_debugfs_gpuva_info);
>    218	
>