From: "Luck, Tony" <tony.luck@intel.com>
To: Rich Felker <dalias@libc.org>, Matthew Wilcox <willy@infradead.org>
Cc: Kees Cook <keescook@chromium.org>,
Ilya Smith <blackzert@gmail.com>,
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Subject: RE: [RFC PATCH v2 0/2] Randomization of address chosen by mmap.
Date: Wed, 28 Mar 2018 21:07:30 +0000 [thread overview]
Message-ID: <3908561D78D1C84285E8C5FCA982C28F7B3B8BC5@ORSMSX110.amr.corp.intel.com> (raw)
In-Reply-To: <20180328000025.GM1436@brightrain.aerifal.cx>
> The default limit of only 65536 VMAs will also quickly come into play
> if consecutive anon mmaps don't get merged. Of course this can be
> raised, but it has significant resource and performance (fork) costs.
Could the random mmap address chooser look for how many existing
VMAs have space before/after and the right attributes to merge with the
new one you want to create? If this is above some threshold (100?) then
pick one of them randomly and allocate the new address so that it will
merge from below/above with an existing one.
That should still give you a very high degree of randomness, but prevent
out of control numbers of VMAs from being created.
-Tony
next prev parent reply other threads:[~2018-03-28 21:07 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-22 16:36 Ilya Smith
2018-03-22 16:36 ` [RFC PATCH v2 1/2] " Ilya Smith
2018-03-22 20:53 ` Andrew Morton
2018-03-23 17:43 ` Ilya Smith
2018-03-22 16:36 ` [RFC PATCH v2 2/2] Architecture defined limit on memory region random shift Ilya Smith
2018-03-22 20:54 ` Andrew Morton
2018-03-23 17:48 ` Ilya Smith
2018-03-23 17:49 ` Ilya Smith
2018-03-22 20:57 ` [RFC PATCH v2 0/2] Randomization of address chosen by mmap Andrew Morton
2018-03-23 17:25 ` Ilya Smith
2018-03-23 12:48 ` Matthew Wilcox
2018-03-23 17:55 ` Ilya Smith
2018-03-26 8:46 ` Michal Hocko
2018-03-26 19:45 ` Ilya Smith
2018-03-27 7:24 ` Michal Hocko
2018-03-27 13:51 ` Ilya Smith
2018-03-27 14:38 ` Michal Hocko
2018-03-28 18:47 ` Ilya Smith
2018-03-27 22:16 ` Theodore Y. Ts'o
2018-03-27 23:58 ` Rich Felker
2018-03-28 18:48 ` Ilya Smith
2018-03-27 22:53 ` Kees Cook
2018-03-27 23:49 ` Matthew Wilcox
2018-03-27 23:57 ` Kees Cook
2018-03-28 0:00 ` Rich Felker
2018-03-28 21:07 ` Luck, Tony [this message]
2018-04-03 0:11 ` Ilya Smith
2018-03-28 21:07 ` Ilya Smith
2018-03-23 18:00 ` Rich Felker
2018-03-23 19:06 ` Matthew Wilcox
2018-03-23 19:16 ` Rich Felker
2018-03-23 19:29 ` Matthew Wilcox
2018-03-23 19:35 ` Rich Felker
2018-03-28 4:50 ` Rob Landley
2018-03-30 7:55 ` Pavel Machek
2018-03-30 9:07 ` Ilya Smith
2018-03-30 9:57 ` Pavel Machek
2018-03-30 11:10 ` Ilya Smith
2018-03-30 13:33 ` Rich Felker
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