Re: [PATCH 0/2] mm,fork,security: introduce MADV_WIPEONFORK

[Kirill A. Shutemov]

On Fri, Aug 04, 2017 at 03:07:28PM -0400, riel@xxxxxxxxxx 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()?

-- 
 Kirill A. Shutemov