Well, no sooner did I say it wasn't time yet, the upstream tip got a flood of changes after 2.6.26 to make them diverge.
The 2.6.26/ patches and 2.6.26/* GIT branches have the code I've just been talking about, and that's the version on which I did the testing I spoke about. The 2.6-current/ patches and main {ptrace-cleanup,tracehook,utrace} branches are now rebased to the post-2.6.26 upstream tip. I hope that the tracehook patch series will not need to change any more at this point. The rebasing of a new utrace series on top of 2.6.26/tracehook is always trivial. Thanks, Roland