Re: [PATCH] error path in setup_arg_pages() missesvm_unacct_memory()

From: Andrew Morton
Date: Tue Sep 13 2005 - 13:38:46 EST


Hugh Dickins <hugh@xxxxxxxxxxx> wrote:
>
> On Tue, 13 Sep 2005, Andrew Morton wrote:
> > Kirill Korotaev <dev@xxxxx> wrote:
> > >
> > > maybe it is worth moving vm_acct_memory() out of
> > > security_vm_enough_memory()?
> >
> > I think that would be saner, yes. That means that the callers would call
> > vm_acct_memory() after security_enough_memory(), if that succeeded.
>
> I don't like that at all. The implementation of its tests is necessarily
> imprecise, but nonetheless, we do prefer primitives which atomically test
> and reserve. We're not moving from request_region to check_region, are we?

I don't think that it's any racier to move the allocation to after the
check than to have it before the check. If we're worried, take mmap_sem -
most place already do that, but not all.

> But change the naming by all means, it was never good,
> and grew worse when "security_" got stuck on the front.

Yes, renaming it to something like alloc_vm_space() would suit.
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