From: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
To: Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Khalid Aziz <khalid.aziz-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>,
Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Russell King - ARM Linux
<linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>,
Andrea Arcangeli
<aarcange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Florian Weimer <fweimer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
John Hubbard <jhubbard-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
Subject: Re: [PATCH 1/2] mm: introduce MAP_FIXED_SAFE
Date: Wed, 13 Dec 2017 04:50:53 -0800 [thread overview]
Message-ID: <20171213125053.GB2384@bombadil.infradead.org> (raw)
In-Reply-To: <20171213092550.2774-2-mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
On Wed, Dec 13, 2017 at 10:25:49AM +0100, Michal Hocko wrote:
> +++ b/mm/mmap.c
> @@ -1342,6 +1342,10 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
> if (!(file && path_noexec(&file->f_path)))
> prot |= PROT_EXEC;
>
> + /* force arch specific MAP_FIXED handling in get_unmapped_area */
> + if (flags & MAP_FIXED_SAFE)
> + flags |= MAP_FIXED;
> +
> if (!(flags & MAP_FIXED))
> addr = round_hint_to_min(addr);
>
We're up to 22 MAP_ flags now. We'll run out soon. Let's preserve half
of a flag by giving userspace the definition:
#define MAP_FIXED_SAFE (MAP_FIXED | _MAP_NOT_HINT)
then in here:
if ((flags & _MAP_NOT_HINT) && !(flags & MAP_FIXED))
return -EINVAL;
Now we can use _MAP_NOT_HINT all by itself in the future to mean
something else.
next prev parent reply other threads:[~2017-12-13 12:50 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-13 9:25 [PATCH v2 0/2] mm: introduce MAP_FIXED_SAFE Michal Hocko
2017-12-13 9:25 ` [PATCH 1/2] " Michal Hocko
[not found] ` <20171213092550.2774-2-mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2017-12-13 12:50 ` Matthew Wilcox [this message]
2017-12-13 13:01 ` Michal Hocko
2017-12-13 9:25 ` [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map Michal Hocko
2017-12-16 0:49 ` [2/2] " Andrei Vagin
2017-12-18 9:13 ` Michal Hocko
2017-12-18 18:12 ` Andrei Vagin
2017-12-13 9:31 ` [PATCH 1/2] mmap.2: document new MAP_FIXED_SAFE flag Michal Hocko
2017-12-13 9:31 ` [PATCH 2/2] mmap.2: MAP_FIXED updated documentation Michal Hocko
2017-12-13 12:55 ` Pavel Machek
2017-12-13 13:03 ` Cyril Hrubis
2017-12-13 13:04 ` Michal Hocko
2017-12-13 13:09 ` Pavel Machek
2017-12-13 13:16 ` Michal Hocko
[not found] ` <20171213131640.GJ25185-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2017-12-13 13:21 ` Pavel Machek
2017-12-13 13:35 ` Michal Hocko
2017-12-13 14:40 ` Cyril Hrubis
2017-12-13 23:19 ` Kees Cook
[not found] ` <CAGXu5jLqE6cUxk-Girx6PG7upEzz8jmu1OH_3LVC26iJc2vTxQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-12-14 7:07 ` Michal Hocko
2017-12-18 19:12 ` Michael Kerrisk (man-pages)
2017-12-18 20:19 ` Kees Cook
2017-12-18 20:33 ` Matthew Wilcox
[not found] ` <CAGXu5jJ289R9koVoHmxcvUWr6XHSZR2p0qq3WtpNyN-iNSvrNQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-12-21 12:38 ` Michael Ellerman
2017-12-21 14:59 ` known bad patch in -mm tree was " Pavel Machek
2017-12-21 15:08 ` Michal Hocko
2017-12-21 22:24 ` Andrew Morton
2017-12-22 0:06 ` Michael Ellerman
2017-12-14 2:52 ` Jann Horn
[not found] ` <CAG48ez0JZ3PVW3vgSXDmDijS+a_5bSX9qNuyggnsB6JTSkKngA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-12-14 5:28 ` John Hubbard
2017-12-14 23:06 ` John Hubbard
[not found] ` <b4fb7b3a-e53e-bf87-53c5-186751a14f4e-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2017-12-14 23:10 ` Jann Horn
[not found] ` <20171213092550.2774-1-mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2017-12-13 12:25 ` [PATCH v2 0/2] mm: introduce MAP_FIXED_SAFE Matthew Wilcox
2017-12-13 12:34 ` Michal Hocko
2017-12-13 17:13 ` Kees Cook
2017-12-15 9:02 ` Michael Ellerman
2017-12-14 0:32 ` Andrew Morton
2017-12-14 1:35 ` David Goldblatt
2017-12-14 1:42 ` David Goldblatt
2017-12-14 12:44 ` Edward Napierala
2017-12-14 13:15 ` Michal Hocko
2017-12-14 14:54 ` Edward Napierala
2017-12-19 12:40 ` David Laight
2017-12-19 12:46 ` Michal Hocko
-- strict thread matches above, loose matches on Subject: below --
2017-11-29 14:42 [PATCH " Michal Hocko
2017-11-29 14:42 ` [PATCH 1/2] " Michal Hocko
2017-12-06 5:15 ` Michael Ellerman
2017-12-06 9:27 ` Michal Hocko
2017-12-06 10:02 ` Michal Hocko
2017-12-07 12:07 ` Pavel Machek
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