linux-kernel - Re: [PATCH 1/2] fs, elf: drop MAP_FIXED usage from elf

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Message-ID: <20171017133324.y2nkse6svunpd5s2@dhcp22.suse.cz>
Date:   Tue, 17 Oct 2017 15:33:24 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Baoquan He <bhe@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Kees Cook <keescook@...omium.org>,
        Jiri Kosina <jkosina@...e.cz>,
        Al Viro <viro@...iv.linux.org.uk>,
        Oleg Nesterov <oleg@...hat.com>, Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH 1/2] fs, elf: drop MAP_FIXED usage from elf_map

On Tue 17-10-17 21:22:46, Baoquan He wrote:
[...]
> And as I said before, then we will still have the
> ungraceful 'mapping total'|'unmapping the rest' method.

yes I haven't touched this part and I guess you are right it can be
removed now, but this was not my primary concern to adddress so there is
still some room for improvements on top. If you want to refactor that
part, then feel free to do so but I think that we should address the
MAP_FIXED part first.

> If from a new code reader's point of view, the newly added elf_vm_mmap()
> plus the existing elf_map() may confuse people more.

Heh, I strongly suspect that this indirection is the last thing that
would make the code hard to grasp. The whole load_elf_binary is a giant
and incomprehensible mess.

-- 
Michal Hocko
SUSE Labs