linux-kernel - Re: [PATCH v2 0/2] mm,fork,security: introduce MADV

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Message-ID: <c8cda773-b28d-f35f-7f18-6735584cb173@redhat.com>
Date:   Fri, 11 Aug 2017 16:11:44 +0200
From:   Florian Weimer <fweimer@...hat.com>
To:     Michal Hocko <mhocko@...nel.org>,
        Colm MacCárthaigh <colm@...costs.net>
Cc:     Kees Cook <keescook@...omium.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Rik van Riel <riel@...hat.com>,
        Will Drewry <wad@...omium.org>, akpm@...ux-foundation.org,
        dave.hansen@...el.com, kirill@...temov.name,
        linux-api@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, luto@...capital.net, mingo@...nel.org
Subject: Re: [PATCH v2 0/2] mm,fork,security: introduce MADV_WIPEONFORK

On 08/11/2017 04:06 PM, Michal Hocko wrote:

> I am sorry to look too insisting here (I have still hard time to reconcile
> myself with the madvise (ab)use) but if we in fact want minherit like
> interface why don't we simply add minherit and make the code which wants
> to use that interface easier to port? Is the only reason that hooking
> into madvise is less code? If yes is that a sufficient reason to justify
> the (ab)use of madvise? If there is a general consensus on that part I
> will shut up and won't object anymore. Arguably MADV_DONTFORK would fit
> into minherit API better as well.

It does, OpenBSD calls it MAP_INHERIT_NONE.

Could you implement MAP_INHERIT_COPY and MAP_INHERIT_SHARE as well?  Or
is changing from MAP_SHARED to MAP_PRIVATE and back impossible?

Thanks,
Florian