Linux kernel 3.12.17 has been out for a week (and there is a vanilla-sources package) but there has benn no corresponding gentoo-sources release. Reproducible: Always
Sorry about that one. It slipped through the cracks. Released. 14 Apr 2014; Michael Pagano <mpagano@gentoo.org> +gentoo-sources-3.12.17.ebuild: Linux patch 3.12.17