Date: Sat, 5 Mar 2011 22:20:51 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
        LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
        pageexec@freemail.hu, Solar Designer <solar@openwall.com>,
        Eugene Teo <eteo@redhat.com>, Brad Spengler <spender@grsecurity.net>,
        Roland McGrath <roland@redhat.com>, Milton Miller <miltonm@bga.com>
Subject: Re: [PATCH v4 3/4] exec: unify do_execve/compat_do_execve code
Message-ID: <20110305212051.GA9937@redhat.com>
References: <20110302162650.GA26810@redhat.com> <20110302162712.GB26810@redhat.com> <20110303114952.B94B.A69D9226@jp.fujitsu.com> <20110303154706.GA22560@redhat.com> <AANLkTimp=mhedXLdrZFqK2QWYvg7MdmUPj3-Q9m2vtTx@mail.gmail.com> <20110305203040.GA7546@redhat.com> <20110305203140.GD7546@redhat.com> <AANLkTi=mce6tzg=vwf45XUQoADA=YbP2QJ2_tpg=QgQE@mail.gmail.com>
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On 03/05, Linus Torvalds wrote:
>
> Ok, everything looks fine to me.
>
> Except looking at this, I don't think this part:
>
> On Sat, Mar 5, 2011 at 12:31 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> >
> > ?struct user_arg_ptr {
> > - ? ? ? const char __user *const __user *native;
> > +#ifdef CONFIG_COMPAT
> > + ? ? ? bool is_compat;
> > +#endif
> > + ? ? ? union {
> > + ? ? ? ? ? ? ? const char __user *const __user *native;
> > + ? ? ? ? ? ? ? compat_uptr_t __user *compat;
> > + ? ? ? } ptr;
> > ?};
>
> will necessarily even compile on an architecture that doesn't have any
> 'compat' support.

Aaaaaaaaaaaaaaaaaah, now this is a really good point.

> Do we even define 'compat_uptr_t' for that case? I don't think so.

Indeed, you are right.

What I was thinking about? I do not know.

> So I suspect you need two of those annoying #ifdef's.

please expect v5 tomorrow.

Oleg.

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