TL;DR: This is a bug caused by GTK Emacs 24 and recent glib (introduced somewhere between 2.33.12 and 2.36.1) when there's no D-BUS session daemon running. It was "fixed" in Emacs git two weeks ago, but you can temporarily work around the problem by running DBUS or by exporting GSETTINGS_BACKEND=memory.
Quoth David Bremner on Jun 12 at 10:31 am: > > Hi All; > > I've noticed some strange behaviour with zombie processes and > notmuch-emacs. > > * 0.15.2 > - start large search, quit (with q) > - zombie is created > - repeat as many times as you like. > - first search to complete, all zombies are gone. > - CPU is not pegged. > > * 0.15.2+174 > - even searches that complete create zombies > - cpu usage of emacs process hits 100% > > Defining the former as "good" and the latter as "bad", > bisect reveals 08fde50bf3a4c5 as the first "bad" commit. > > I am running emacs 24.3.1 on Debian jessie, with linux kernel 3.9.5-1 > from unstable. > > The bug is pretty annoying since it runs down the battery on my > laptop. In a quick test on another machine running Debian wheezy but > still emacs 24.3.1, I don't see any zombies created at all. I'm not sure > what the imprtant variable is, libc, glib, kernel... This is Emacs bug #14474: http://lists.gnu.org/archive/html/bug-gnu-emacs/2013-05/msg00705.html http://lists.gnu.org/archive/html/bug-gnu-emacs/2013-06/msg00002.html Paul Eggert found the same cause that David and I painstakingly tracked down over IRC: http://lists.gnu.org/archive/html/bug-gnu-emacs/2013-05/msg00726.html This workaround was committed to Emacs git master on May 30th in 8dea8fe0: http://lists.gnu.org/archive/html/bug-gnu-emacs/2013-05/msg00752.html