drm/amdgpu: Fix potential double free and null pointer dereference

In amdgpu_get_xgmi_hive(), we should not call kfree() after
kobject_put() as the PUT will call kfree().

In amdgpu_device_ip_init(), we need to check the returned *hive*
which can be NULL before we dereference it.

Signed-off-by: Liang He <windhl@126.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -2473,6 +2473,11 @@ static int amdgpu_device_ip_init(struct amdgpu_device *adev)
 			if (!amdgpu_sriov_vf(adev)) {
 				struct amdgpu_hive_info *hive = amdgpu_get_xgmi_hive(adev);
 
+				if (WARN_ON(!hive)) {
+					r = -ENOENT;
+					goto init_failed;
+				}
+
 				if (!hive->reset_domain ||
 				    !amdgpu_reset_get_reset_domain(hive->reset_domain)) {
 					r = -ENOENT;

drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c

@@ -386,7 +386,6 @@ struct amdgpu_hive_info *amdgpu_get_xgmi_hive(struct amdgpu_device *adev)
 	if (ret) {
 		dev_err(adev->dev, "XGMI: failed initializing kobject for xgmi hive\n");
 		kobject_put(&hive->kobj);
-		kfree(hive);
 		hive = NULL;
 		goto pro_end;
 	}
@@ -410,7 +409,6 @@ struct amdgpu_hive_info *amdgpu_get_xgmi_hive(struct amdgpu_device *adev)
 				dev_err(adev->dev, "XGMI: failed initializing reset domain for xgmi hive\n");
 				ret = -ENOMEM;
 				kobject_put(&hive->kobj);
-				kfree(hive);
 				hive = NULL;
 				goto pro_end;
 			}