From: Michal Hocko <mhocko@kernel.org> To: Matthew Wilcox <willy@infradead.org> Cc: linux-api@vger.kernel.org, Khalid Aziz <khalid.aziz@oracle.com>, Michael Ellerman <mpe@ellerman.id.au>, Andrew Morton <akpm@linux-foundation.org>, Russell King - ARM Linux <linux@armlinux.org.uk>, Andrea Arcangeli <aarcange@redhat.com>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org, Florian Weimer <fweimer@redhat.com>, John Hubbard <jhubbard@nvidia.com> Subject: Re: [PATCH 1/2] mm: introduce MAP_FIXED_SAFE Date: Wed, 13 Dec 2017 14:01:35 +0100 [thread overview] Message-ID: <20171213130135.GG25185@dhcp22.suse.cz> (raw) In-Reply-To: <20171213125053.GB2384@bombadil.infradead.org> On Wed 13-12-17 04:50:53, Matthew Wilcox wrote: > 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) I've already tried to explain why this cannot be a modifier for MAP_FIXED. Read about the backward compatibility note... Or do I misunderstand what you are saying here? > 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. -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: Matthew Wilcox <willy@infradead.org> Cc: linux-api@vger.kernel.org, Khalid Aziz <khalid.aziz@oracle.com>, Michael Ellerman <mpe@ellerman.id.au>, Andrew Morton <akpm@linux-foundation.org>, Russell King - ARM Linux <linux@armlinux.org.uk>, Andrea Arcangeli <aarcange@redhat.com>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org, Florian Weimer <fweimer@redhat.com>, John Hubbard <jhubbard@nvidia.com> Subject: Re: [PATCH 1/2] mm: introduce MAP_FIXED_SAFE Date: Wed, 13 Dec 2017 14:01:35 +0100 [thread overview] Message-ID: <20171213130135.GG25185@dhcp22.suse.cz> (raw) In-Reply-To: <20171213125053.GB2384@bombadil.infradead.org> On Wed 13-12-17 04:50:53, Matthew Wilcox wrote: > 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) I've already tried to explain why this cannot be a modifier for MAP_FIXED. Read about the backward compatibility note... Or do I misunderstand what you are saying here? > 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. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-12-13 13:01 UTC|newest] Thread overview: 125+ 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 ` Michal Hocko 2017-12-13 9:25 ` Michal Hocko 2017-12-13 9:25 ` [PATCH 1/2] " Michal Hocko 2017-12-13 9:25 ` Michal Hocko 2017-12-13 9:25 ` Michal Hocko 2017-12-13 12:50 ` Matthew Wilcox 2017-12-13 12:50 ` Matthew Wilcox 2017-12-13 12:50 ` Matthew Wilcox 2017-12-13 13:01 ` Michal Hocko [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 2017-12-13 9:25 ` Michal Hocko 2017-12-13 9:25 ` Michal Hocko 2017-12-16 0:49 ` [2/2] " Andrei Vagin 2017-12-18 9:13 ` Michal Hocko 2017-12-18 9:13 ` Michal Hocko 2017-12-18 18:12 ` Andrei Vagin 2017-12-18 18:12 ` Andrei Vagin 2017-12-18 18:49 ` [PATCH] mm: don't use the same value for MAP_FIXED_SAFE and MAP_SYNC Andrei Vagin 2017-12-18 18:49 ` Andrei Vagin 2017-12-18 20:41 ` Michal Hocko 2017-12-18 20:41 ` Michal Hocko 2018-04-18 10:51 ` [PATCH 2/2] fs, elf: drop MAP_FIXED usage from elf_map Tetsuo Handa 2018-04-18 10:51 ` Tetsuo Handa 2018-04-18 11:33 ` Michal Hocko 2018-04-18 11:43 ` Tetsuo Handa 2018-04-18 11:55 ` Michal Hocko 2018-04-18 14:07 ` [PATCH v2] fs, elf: don't complain MAP_FIXED_NOREPLACE unless -EEXIST error Tetsuo Handa 2018-04-19 5:57 ` Michal Hocko 2017-12-13 9:31 ` [PATCH 1/2] mmap.2: document new MAP_FIXED_SAFE flag Michal Hocko 2017-12-13 9:31 ` Michal Hocko 2017-12-13 9:31 ` Michal Hocko 2017-12-13 9:31 ` [PATCH 2/2] mmap.2: MAP_FIXED updated documentation Michal Hocko 2017-12-13 9:31 ` Michal Hocko 2017-12-13 9:31 ` Michal Hocko 2017-12-13 12:55 ` Pavel Machek 2017-12-13 13:03 ` Cyril Hrubis 2017-12-13 13:03 ` Cyril Hrubis 2017-12-13 13:03 ` Cyril Hrubis 2017-12-13 13:04 ` Michal Hocko 2017-12-13 13:04 ` Michal Hocko 2017-12-13 13:09 ` Pavel Machek 2017-12-13 13:16 ` Michal Hocko 2017-12-13 13:16 ` Michal Hocko 2017-12-13 13:21 ` Pavel Machek 2017-12-13 13:21 ` Pavel Machek 2017-12-13 13:35 ` Michal Hocko 2017-12-13 13:35 ` Michal Hocko 2017-12-13 14:40 ` Cyril Hrubis 2017-12-13 14:40 ` Cyril Hrubis 2017-12-13 14:40 ` Cyril Hrubis 2017-12-13 23:19 ` Kees Cook 2017-12-13 23:19 ` Kees Cook 2017-12-14 7:07 ` Michal Hocko 2017-12-14 7:07 ` Michal Hocko 2017-12-14 7:07 ` Michal Hocko 2017-12-18 19:12 ` Michael Kerrisk (man-pages) 2017-12-18 19:12 ` Michael Kerrisk (man-pages) 2017-12-18 20:19 ` Kees Cook 2017-12-18 20:19 ` Kees Cook 2017-12-18 20:33 ` Matthew Wilcox 2017-12-18 20:33 ` Matthew Wilcox 2017-12-21 12:38 ` Michael Ellerman 2017-12-21 12:38 ` Michael Ellerman 2017-12-21 12:38 ` Michael Ellerman 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 15:08 ` Michal Hocko 2017-12-21 22:24 ` Andrew Morton 2017-12-21 22:24 ` Andrew Morton 2017-12-21 22:24 ` Andrew Morton 2017-12-22 0:06 ` Michael Ellerman 2017-12-22 0:06 ` Michael Ellerman 2017-12-22 0:06 ` Michael Ellerman 2017-12-14 2:52 ` Jann Horn 2017-12-14 2:52 ` Jann Horn 2017-12-14 5:28 ` John Hubbard 2017-12-14 5:28 ` John Hubbard 2017-12-14 5:28 ` John Hubbard 2017-12-14 5:28 ` John Hubbard 2017-12-14 23:06 ` John Hubbard 2017-12-14 23:06 ` John Hubbard 2017-12-14 23:06 ` John Hubbard 2017-12-14 23:10 ` Jann Horn 2017-12-14 23:10 ` Jann Horn 2017-12-14 23:10 ` Jann Horn 2017-12-13 12:25 ` [PATCH v2 0/2] mm: introduce MAP_FIXED_SAFE Matthew Wilcox 2017-12-13 12:25 ` Matthew Wilcox 2017-12-13 12:25 ` Matthew Wilcox 2017-12-13 12:34 ` Michal Hocko 2017-12-13 12:34 ` Michal Hocko 2017-12-13 17:13 ` Kees Cook 2017-12-13 17:13 ` Kees Cook 2017-12-13 17:13 ` Kees Cook 2017-12-15 9:02 ` Michael Ellerman 2017-12-15 9:02 ` Michael Ellerman 2017-12-14 0:32 ` Andrew Morton 2017-12-14 0:32 ` Andrew Morton 2017-12-14 0:32 ` Andrew Morton 2017-12-14 0:32 ` Andrew Morton 2017-12-14 1:35 ` David Goldblatt 2017-12-14 1:42 ` 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 13:15 ` Michal Hocko 2017-12-14 14:54 ` Edward Napierala 2017-12-14 14:54 ` Edward Napierala 2017-12-19 12:40 ` David Laight 2017-12-19 12:40 ` David Laight 2017-12-19 12:46 ` Michal Hocko 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 2017-11-29 14:42 ` Michal Hocko 2017-11-29 14:42 ` Michal Hocko 2017-12-06 5:15 ` Michael Ellerman 2017-12-06 5:15 ` Michael Ellerman 2017-12-06 9:27 ` Michal Hocko 2017-12-06 9:27 ` Michal Hocko 2017-12-06 10:02 ` Michal Hocko 2017-12-06 10:02 ` Michal Hocko 2017-12-07 12:07 ` Pavel Machek 2017-12-07 12:07 ` Pavel Machek
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