Comment 3 for bug 1154813

I run raring-proposed as well, and I cannot replicate this. But this does ring a bell. We got similar reports with earlier libudev0 versions as well, and eventually reverted an upstream commit:

Unfortunately this never got debugged properly, as I never got access to a machine which exhibits this behaviour. Also, this works just fine on Debian, Fedora, Arch, and other distros, so I guess we have some bug in our initramfs-tools/upstart interaction which is exhibited by using a nonblocking socket. For now I'll apply that patch to libudev1.