On Mon, Sep 28, 2020 at 09:46:56PM -0700, Andrew Morton wrote: > On Tue, 29 Sep 2020 02:17:19 +0100 Matthew Wilcox <wi...@infradead.org> wrote: > > > On Mon, Sep 28, 2020 at 06:03:07PM -0700, Andrew Morton wrote: > > > On Sat, 26 Sep 2020 22:39:19 +0100 "Matthew Wilcox (Oracle)" > > > <wi...@infradead.org> wrote: > > > > > > > Here is a very rare race which leaks memory: > > > > > > Not worth a cc:stable? > > > > Yes, it probably should have been. > > Have you a feeling for how often this occurs?
I doubt it happens often. I don't think I could construct a workload to make it happen frequently. Maybe more often with a virtualised workload where a thread can be preempted between instructions. > > I just assume the stablebot will > > pick up anything that has a Fixes: tag. > > We asked them not to do that for mm/ patches. Crazy stuff was getting > backported. That's a shame. I'll try to remember to cc them explicitly in the future. > > Although I'm now thinking of making that comment into kernel-doc and > > turning it into advice to the caller rather than an internal note to > > other mm developers. > > hm. But what action could the caller take? The explanatory comment > seems OK to me. Use compound pages instead of non-compound pages. Although Linus has asked that people stop using __get_free_pages(), so maybe that will be the direction we go in. https://lore.kernel.org/lkml/ca+55afwyxj+topajznc5mpj-25xblaeu8ijp8ztyhma3lxf...@mail.gmail.com/
