Re: [PATCH] binfmt: turn MAX_ARG_PAGES into a sysctl tunable

[Ingo Molnar <mingo@elte.hu>]

* Arjan van de Ven <arjan@linux.intel.com> wrote:

> Ingo Molnar wrote:
> >at copy_strings_kernel() time we dont yet know where in the target VM to 
> >install the pages. A binformat might want to install all sorts of stuff 
> >on the stack first, before it constructs the envp and copies the strings 
> >themselves. So we dont know the precise alignment needed.
> >
> >delaying the copying to setup_arg_pages() time does not seem to work 
> >either, because that gets called after the old MM has been destroyed.
> >
> >[ delaying the copying will also change behavior in error cases - 
> >  instead of returning with an error if the string pointers are bad 
> >  we'll have to kill the execve()ing process. ]
> >
> >am i missing something?
> 
> we could always just have the binfmt use mremap() equivalent to move 
> it into the place it wants...

i dont think so, these things on the stack are not page aligned.

	Ingo