[PATCH v2] drm/amdgpu: Fix possible NULL pointer dereference

[Li Huafei]

Fix the potential NULL pointer dereference on mem_ranges in
amdgpu_discovery_get_nps_info(). Additionally, assign the output
parameters nps_type and range_cnt after the kvzalloc() call to prevent
modifying the output parameters in case of an error return.

Fixes: b194d21b9bcc ("drm/amdgpu: Use NPS ranges from discovery table")
Signed-off-by: Li Huafei <lihuafei1 at huawei.com>
---
Changes in v2:
 - kvzalloc() call uses 'nps_info->v1.count' instead of '*range_cnt'
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
index 4bd61c169ca8..9a0b1b208a9d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
@@ -1757,11 +1757,13 @@ int amdgpu_discovery_get_nps_info(struct amdgpu_device *adev,
 
 	switch (le16_to_cpu(nps_info->v1.header.version_major)) {
 	case 1:
-		*nps_type = nps_info->v1.nps_type;
-		*range_cnt = nps_info->v1.count;
 		mem_ranges = kvzalloc(
-			*range_cnt * sizeof(struct amdgpu_gmc_memrange),
+			nps_info->v1.count * sizeof(struct amdgpu_gmc_memrange),
 			GFP_KERNEL);
+		if (!mem_ranges)
+			return -ENOMEM;
+		*nps_type = nps_info->v1.nps_type;
+		*range_cnt = nps_info->v1.count;
 		for (i = 0; i < *range_cnt; i++) {
 			mem_ranges[i].base_address =
 				nps_info->v1.instance_info[i].base_address;
-- 
2.25.1