Sorry about replying to an old thread. I've had this problem when using criu, and fixed it by changing the permissions recorded in the files.img file in the checkpoint dir, before restoring from it. You can use "crit show" to decode the file to json format and replace "mode": 16749 with "mode": 16877, before encoding the json back to .img format using "crit encode". Writing about this workaround in case anyone finds this thread while searching for the error message.