On Mon, Jun 12, 2017 at 09:17:34PM +0200, Greg KH wrote: > On Mon, Jun 12, 2017 at 09:31:51AM -0700, Paul E. McKenney wrote: > > On Mon, Jun 12, 2017 at 02:17:59PM +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > > > > > The patch below does not apply to the 4.9-stable tree. > > > If someone wants it applied there, or to any other stable or longterm > > > tree, then please email the backport, including the original git commit > > > id to <stable@xxxxxxxxxxxxxxx>. > > > > Indeed, this won't apply cleanly to 4.9 and earlier because of some > > changes to the way SRCU works. And if you try to make the obvious > > adjustments to make the patch apply, you will break SRCU. > > Oh good, I was wondering about that, I thought I had backported it > properly, but then I figured I really don't know how rcu works in > detail, so decided to just punt and reject it :) If it makes you feel better, the reason I know that it breaks SRCU is because I backported the patches early this morning before I was fully awake. Fortunately, rcutorture protested vigorously, saying this about a 30-minute run: WARNING: Summary: Bugs: 3494 Call Traces: 3494 Paolo pointed out at least one of the additional patches that would have to be backported along with this one. If people start seeing failures on the older kernels, I will of course make sure that the backport happens. Thanx, Paul