From: Rik van Riel <riel@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
fweimer@redhat.com, colm@allcosts.net, akpm@linux-foundation.org,
rppt@linux.vnet.ibm.com, keescook@chromium.org,
luto@amacapital.net, wad@chromium.org, mingo@kernel.org
Subject: Re: [PATCH 0/2] mm,fork,security: introduce MADV_WIPEONFORK
Date: Sat, 05 Aug 2017 11:21:44 -0400 [thread overview]
Message-ID: <1501946504.6577.9.camel@redhat.com> (raw)
In-Reply-To: <20170804234435.lkblljl3f3ud2spm@node.shutemov.name>
On Sat, 2017-08-05 at 02:44 +0300, Kirill A. Shutemov wrote:
> On Fri, Aug 04, 2017 at 03:07:28PM -0400, riel@redhat.com wrote:
> > [resend because half the recipients got dropped due to IPv6
> > firewall issues]
> >
> > Introduce MADV_WIPEONFORK semantics, which result in a VMA being
> > empty in the child process after fork. This differs from
> > MADV_DONTFORK
> > in one important way.
> >
> > If a child process accesses memory that was MADV_WIPEONFORK, it
> > will get zeroes. The address ranges are still valid, they are just
> > empty.
>
> I feel like we are repeating mistake we made with MADV_DONTNEED.
>
> MADV_WIPEONFORK would require a specific action from kernel, ignoring
> the /advise/ would likely lead to application misbehaviour.
>
> Is it something we really want to see from madvise()?
We already have various mandatory madvise behaviors in Linux,
including MADV_REMOVE, MADV_DONTFORK, and MADV_DONTDUMP.
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WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
fweimer@redhat.com, colm@allcosts.net, akpm@linux-foundation.org,
rppt@linux.vnet.ibm.com, keescook@chromium.org,
luto@amacapital.net, wad@chromium.org, mingo@kernel.org
Subject: Re: [PATCH 0/2] mm,fork,security: introduce MADV_WIPEONFORK
Date: Sat, 05 Aug 2017 11:21:44 -0400 [thread overview]
Message-ID: <1501946504.6577.9.camel@redhat.com> (raw)
In-Reply-To: <20170804234435.lkblljl3f3ud2spm@node.shutemov.name>
On Sat, 2017-08-05 at 02:44 +0300, Kirill A. Shutemov wrote:
> On Fri, Aug 04, 2017 at 03:07:28PM -0400, riel@redhat.com wrote:
> > [resend because half the recipients got dropped due to IPv6
> > firewall issues]
> >
> > Introduce MADV_WIPEONFORK semantics, which result in a VMA being
> > empty in the child process after fork. This differs from
> > MADV_DONTFORK
> > in one important way.
> >
> > If a child process accesses memory that was MADV_WIPEONFORK, it
> > will get zeroes. The address ranges are still valid, they are just
> > empty.
>
> I feel like we are repeating mistake we made with MADV_DONTNEED.
>
> MADV_WIPEONFORK would require a specific action from kernel, ignoring
> the /advise/ would likely lead to application misbehaviour.
>
> Is it something we really want to see from madvise()?
We already have various mandatory madvise behaviors in Linux,
including MADV_REMOVE, MADV_DONTFORK, and MADV_DONTDUMP.
next prev parent reply other threads:[~2017-08-05 15:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-04 19:07 [PATCH 0/2] mm,fork,security: introduce MADV_WIPEONFORK riel
2017-08-04 19:07 ` riel
2017-08-04 19:07 ` [PATCH 1/2] x86,mpx: make mpx depend on x86-64 to free up VMA flag riel
2017-08-04 19:07 ` riel
2017-08-04 19:25 ` Dave Hansen
2017-08-04 19:25 ` Dave Hansen
2017-08-04 19:07 ` [PATCH 2/2] mm,fork: introduce MADV_WIPEONFORK riel
2017-08-04 19:07 ` riel
2017-08-04 23:09 ` Mike Kravetz
2017-08-04 23:09 ` Mike Kravetz
2017-08-05 14:05 ` Rik van Riel
2017-08-05 14:05 ` Rik van Riel
2017-08-14 15:45 ` kbuild test robot
2017-08-04 23:44 ` [PATCH 0/2] mm,fork,security: " Kirill A. Shutemov
2017-08-04 23:44 ` Kirill A. Shutemov
2017-08-05 15:21 ` Rik van Riel [this message]
2017-08-05 15:21 ` Rik van Riel
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