From: Oleg Nesterov <oleg@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Baoquan He <bhe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Kees Cook <keescook@chromium.org>, Jiri Kosina <jkosina@suse.cz>,
Al Viro <viro@zeniv.linux.org.uk>, Ingo Molnar <mingo@elte.hu>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: MAP_FIXED for ELF mappings
Date: Thu, 5 Oct 2017 18:33:20 +0200 [thread overview]
Message-ID: <20171005163320.GA20848@redhat.com> (raw)
In-Reply-To: <20171004151700.k4fvivvmi7pm5sl7@dhcp22.suse.cz>
On 10/04, Michal Hocko wrote:
>
> On Wed 04-10-17 23:12:38, Baoquan He wrote:
> > if (total_size) {
> > total_size = ELF_PAGEALIGN(total_size);
> > - map_addr = vm_mmap(filep, addr, total_size, prot, flags, off);
> > - if (!BAD_ADDR(map_addr))
> > - vm_munmap(map_addr+size, total_size-size);
> > - } else
> > - map_addr = vm_mmap(filep, addr, size, prot, flags, off);
> > + addr = get_unmapped_area(file, addr, total_size, off, flags);
>
> So how does this prevent clobbering an existing VMA when flags contains
> MAP_FIXED?
I got lost...
this is just cleanup, it should not change the behaviour, with or without
MAP_FIXED. It just avoids the mmap(total_size) + munmap(extra_size).
Oleg.
next prev parent reply other threads:[~2017-10-05 16:33 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 7:50 MAP_FIXED for ELF mappings Michal Hocko
2017-10-04 7:59 ` Michal Hocko
2017-10-04 15:03 ` Baoquan He
2017-10-04 15:11 ` Michal Hocko
2017-10-04 15:12 ` Baoquan He
2017-10-04 15:17 ` Michal Hocko
2017-10-04 15:37 ` Baoquan He
2017-10-04 17:12 ` Michal Hocko
2017-10-04 17:15 ` Linus Torvalds
2017-10-04 17:28 ` Michal Hocko
2017-10-05 16:33 ` Oleg Nesterov [this message]
2017-10-05 16:42 ` Michal Hocko
2017-10-16 13:44 ` [PATCH 0/2] fs, elf: get rid of MAP_FIXED from the loader Michal Hocko
2017-10-16 13:44 ` [PATCH 1/2] fs, elf: drop MAP_FIXED usage from elf_map Michal Hocko
2017-10-16 16:39 ` Kees Cook
2017-10-16 19:00 ` Michal Hocko
2017-10-16 20:02 ` James Hogan
2017-10-17 7:37 ` Michal Hocko
2017-10-17 8:35 ` James Hogan
2017-10-17 8:56 ` Michal Hocko
2017-10-17 12:26 ` Baoquan He
2017-10-17 12:56 ` Michal Hocko
2017-10-17 13:22 ` Baoquan He
2017-10-17 13:33 ` Michal Hocko
2017-10-17 13:42 ` Baoquan He
2017-10-16 13:44 ` [PATCH 2/2] fs, elf: drop MAP_FIXED from initial ET_DYN segment Michal Hocko
2017-10-16 16:44 ` Kees Cook
2017-10-16 18:43 ` Michal Hocko
2017-10-16 19:38 ` Kees Cook
2017-10-17 9:04 ` Michal Hocko
2017-10-17 20:01 ` Kees Cook
2017-10-19 11:20 ` Michal Hocko
2017-10-19 17:19 ` Kees Cook
2017-10-20 8:45 ` Michal Hocko
2017-10-20 14:12 ` Kees Cook
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