[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 <lihuaf...@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