Messages in this thread | | | Date | Sun, 10 May 2009 19:44:54 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen |
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On Sun, May 10, 2009 at 07:39:12PM +0800, KOSAKI Motohiro wrote: > >> > So if that's what they want, let them have it to their heart's content. > >> > > >> > You know it's normal for many users/apps to care only about the result. > >> > When they want something but cannot get it from the smarter version of > >> > PROT_EXEC heuristics, they will go on to devise more complicated tricks. > >> > > >> > In the end both sides loose. > >> > > >> > If the abused case is important enough, then let's introduce a feature > >> > to explicitly prioritize the pages. But let's leave the PROT_EXEC case > >> > simple. > >> > >> No. > >> explicit priotize mechanism don't solve problem anyway. application > >> developer don't know end-user environment. > >> they can't mark proper page priority. > > > > So it's simply wrong for an application to prioritize itself and is > > not fair gaming and hence should be blamed. I doubt any application > > aimed for a wide audience will do this insane hack. > > There already are. > some application don't interest strict PROT_ setting.
> They always use mmap(PROT_READ | PROT_WRITE | PROT_EXEC) for anycase. > Please google it. you can find various example.
How widely is PROT_EXEC abused? Would you share some of your google results?
Thanks, Fengguang
> > > But specific > > targeted applications are more likely to do all tricks which fits > > their needs&environment, and likely they are doing so for good reasons > > and are aware of the consequences.
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