drm/amdgpu: prevent memory leaks in AMDGPU_CS ioctl

Error out if the AMDGPU_CS ioctl is called with multiple SYNCOBJ_OUT and/or
TIMELINE_SIGNAL chunks, since otherwise the last chunk wins while the
allocated array as well as the reference counts of sync objects are leaked.
Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1143,6 +1143,9 @@ static int amdgpu_cs_process_syncobj_out_dep(struct amdgpu_cs_parser *p,
 	num_deps = chunk->length_dw * 4 /
 		sizeof(struct drm_amdgpu_cs_chunk_sem);
 
+	if (p->post_deps)
+		return -EINVAL;
+
 	p->post_deps = kmalloc_array(num_deps, sizeof(*p->post_deps),
 				     GFP_KERNEL);
 	p->num_post_deps = 0;
@@ -1166,8 +1169,7 @@ static int amdgpu_cs_process_syncobj_out_dep(struct amdgpu_cs_parser *p,
 
 
 static int amdgpu_cs_process_syncobj_timeline_out_dep(struct amdgpu_cs_parser *p,
-						      struct amdgpu_cs_chunk
-						      *chunk)
+						      struct amdgpu_cs_chunk *chunk)
 {
 	struct drm_amdgpu_cs_chunk_syncobj *syncobj_deps;
 	unsigned num_deps;
@@ -1177,6 +1179,9 @@ static int amdgpu_cs_process_syncobj_timeline_out_dep(struct amdgpu_cs_parser *p
 	num_deps = chunk->length_dw * 4 /
 		sizeof(struct drm_amdgpu_cs_chunk_syncobj);
 
+	if (p->post_deps)
+		return -EINVAL;
+
 	p->post_deps = kmalloc_array(num_deps, sizeof(*p->post_deps),
 				     GFP_KERNEL);
 	p->num_post_deps = 0;