[kbuild] drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c:1433 amdgpu_discovery_get_vcn_info() error: buffer overflow 'adev->vcn.vcn_codec_disable_mask' 2 <= 3

[Dan Carpenter]

[ kbuild bot sent this warning on May 4 but I never heard back and it's
  May 27 now so sending a duplicate warning is probably for the best. -dan]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  master
head:   7e284070abe53d448517b80493863595af4ab5f0
commit: 622469c87fc3e6c90a980be3e2287d82bd55c977 drm/amdgpu/discovery: add a function to parse the vcn info table
config: arc-randconfig-m031-20220524 (https://download.01.org/0day-ci/archive/20220527/202205271546.oV14N2r8-lkp@intel.com/config )
compiler: arceb-elf-gcc (GCC) 11.3.0

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp at intel.com>
Reported-by: Dan Carpenter <dan.carpenter at oracle.com>

smatch warnings:
drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c:1433 amdgpu_discovery_get_vcn_info() error: buffer overflow 'adev->vcn.vcn_codec_disable_mask' 2 <= 3

vim +1433 drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c

622469c87fc3e6 Alex Deucher 2022-03-30  1403  int amdgpu_discovery_get_vcn_info(struct amdgpu_device *adev)
622469c87fc3e6 Alex Deucher 2022-03-30  1404  {
622469c87fc3e6 Alex Deucher 2022-03-30  1405  	struct binary_header *bhdr;
622469c87fc3e6 Alex Deucher 2022-03-30  1406  	union vcn_info *vcn_info;
622469c87fc3e6 Alex Deucher 2022-03-30  1407  	u16 offset;
622469c87fc3e6 Alex Deucher 2022-03-30  1408  	int v;
622469c87fc3e6 Alex Deucher 2022-03-30  1409  
622469c87fc3e6 Alex Deucher 2022-03-30  1410  	if (!adev->mman.discovery_bin) {
622469c87fc3e6 Alex Deucher 2022-03-30  1411  		DRM_ERROR("ip discovery uninitialized\n");
622469c87fc3e6 Alex Deucher 2022-03-30  1412  		return -EINVAL;
622469c87fc3e6 Alex Deucher 2022-03-30  1413  	}
622469c87fc3e6 Alex Deucher 2022-03-30  1414  
622469c87fc3e6 Alex Deucher 2022-03-30  1415  	if (adev->vcn.num_vcn_inst > VCN_INFO_TABLE_MAX_NUM_INSTANCES) {

Capped to 4

622469c87fc3e6 Alex Deucher 2022-03-30  1416  		dev_err(adev->dev, "invalid vcn instances\n");
622469c87fc3e6 Alex Deucher 2022-03-30  1417  		return -EINVAL;
622469c87fc3e6 Alex Deucher 2022-03-30  1418  	}
622469c87fc3e6 Alex Deucher 2022-03-30  1419  
622469c87fc3e6 Alex Deucher 2022-03-30  1420  	bhdr = (struct binary_header *)adev->mman.discovery_bin;
622469c87fc3e6 Alex Deucher 2022-03-30  1421  	offset = le16_to_cpu(bhdr->table_list[VCN_INFO].offset);
622469c87fc3e6 Alex Deucher 2022-03-30  1422  
622469c87fc3e6 Alex Deucher 2022-03-30  1423  	if (!offset) {
622469c87fc3e6 Alex Deucher 2022-03-30  1424  		dev_err(adev->dev, "invalid vcn table offset\n");
622469c87fc3e6 Alex Deucher 2022-03-30  1425  		return -EINVAL;
622469c87fc3e6 Alex Deucher 2022-03-30  1426  	}
622469c87fc3e6 Alex Deucher 2022-03-30  1427  
622469c87fc3e6 Alex Deucher 2022-03-30  1428  	vcn_info = (union vcn_info *)(adev->mman.discovery_bin + offset);
622469c87fc3e6 Alex Deucher 2022-03-30  1429  
622469c87fc3e6 Alex Deucher 2022-03-30  1430  	switch (le16_to_cpu(vcn_info->v1.header.version_major)) {
622469c87fc3e6 Alex Deucher 2022-03-30  1431  	case 1:
622469c87fc3e6 Alex Deucher 2022-03-30  1432  		for (v = 0; v < adev->vcn.num_vcn_inst; v++) {
622469c87fc3e6 Alex Deucher 2022-03-30 @1433  			adev->vcn.vcn_codec_disable_mask[v] =

But this array doesn't have 4 elements

622469c87fc3e6 Alex Deucher 2022-03-30  1434  				le32_to_cpu(vcn_info->v1.instance_info[v].fuse_data.all_bits);
622469c87fc3e6 Alex Deucher 2022-03-30  1435  		}
622469c87fc3e6 Alex Deucher 2022-03-30  1436  		break;
622469c87fc3e6 Alex Deucher 2022-03-30  1437  	default:
622469c87fc3e6 Alex Deucher 2022-03-30  1438  		dev_err(adev->dev,
622469c87fc3e6 Alex Deucher 2022-03-30  1439  			"Unhandled VCN info table %d.%d\n",
622469c87fc3e6 Alex Deucher 2022-03-30  1440  			le16_to_cpu(vcn_info->v1.header.version_major),
622469c87fc3e6 Alex Deucher 2022-03-30  1441  			le16_to_cpu(vcn_info->v1.header.version_minor));
622469c87fc3e6 Alex Deucher 2022-03-30  1442  		return -EINVAL;
622469c87fc3e6 Alex Deucher 2022-03-30  1443  	}
622469c87fc3e6 Alex Deucher 2022-03-30  1444  	return 0;
f39f5bb1c9d68d Xiaojie Yuan 2019-06-20  1445  }

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp 
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