MAINT-7228 Vertex buffer allocation failure handling

indra/newview/lldrawpoolavatar.cpp

@@ -1613,6 +1613,14 @@ void LLDrawPoolAvatar::updateRiggedFaceVertexBuffer(
 		}
 	}
 
+	if (buffer.isNull() ||
+		buffer->getNumVerts() != vol_face.mNumVertices ||
+		buffer->getNumIndices() != vol_face.mNumIndices)
+	{
+		// Allocation failed
+		return;
+	}
+
 	if (sShaderLevel <= 0 && face->mLastSkinTime < avatar->getLastSkinTime())
 	{
 		//perform software vertex skinning for this face