there are two issues this patch series attempts to fix. First one is
something that has been broken since MMF_UNSTABLE flag introduction
and I guess we should backport it stable trees (patch 1). The other
issue has been brought up by Wenwei Tao and Tetsuo Handa has created
a test case to trigger it very reliably. I am not yet sure this is a
stable material because the test case is rather artificial. If there is
a demand for the stable backport I will prepare it, of course, though.
I hope I've done the second patch correctly but I would definitely
appreciate some more eyes on it. Hence CCing Andrea and Kirill. My
previous attempt with some more context was posted here
My testing didn't show anything unusual with these two applied on top of
the mmotm tree.