Arrgh. How does an article titled "All about Linux signals" not even mention the signalfd() syscall once? Folks: if you're on Linux and need to use signals (i.e. you're reading this article for any practical reason), you need to be using signalfd(). It's not portable to other OSes, but it solves pretty much all the reentrancy and synchronization issues discussed both here and in the article in a very clean way. You get a file descriptor on which you can block cleanly (c.f. select/poll/epoll) and from which you read event notifications on received signals.

Seriously, use it. And OP: please update the blog post to at least point people at it. There's no excuse on a modern linux system for trying to use anything else.