On Wed, Aug 02, 2017 at 06:22:49PM +0200, Michal Hocko wrote: > ESRCH refers to "no such process". Strictly speaking userfaultfd code is > about a mm which is gone but that is a mere detail. In fact the owner of Well this whole issue about which retval, is about a mere detail in the first place, so I don't think you can discount all other mere details as irrelevant in the evaluation of a change to solve a mere detail. > But as I've said, this might be really risky to change. My impression > was that userfaultfd is not widely used yet and those can be fixed > easily but if that is not the case then we have to live with the current > ENOSPC. The only change would be for userfaultfd non cooperative mode, and CRIU is the main user of that. So I think it is up to Mike to decide, I'm fine either ways. I certainly agree ESRCH could be a slightly better fit, I only wanted to clarify it's not a 100% match either.