How to make security check atomic?

[weilitao]

Hello,

Sorry it may be a question not an issue.
From the comment of list method source:
// XXX the security check above is not atomic, so in theory a race condition could
// result in exposing private data

So how to make security check atomic?

[gdad-s-river]

I'm trying to Understand Meteor Todos as well, and I do not know what atomic means, and when there could be a race condition (and of what). I've the same question that @weilitao asked.

[AurelienC]

@gdad-s-river An atomic operation is an operation realized in one time, not paused by another process.