Re: [PATCH -mm] vmscan: make mapped executable pages the first class citizen

KOSAKI Motohiro
2009-05-10T11:45:44Z

>> > 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.

> 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.