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Date: Wed, 7 Sep 2011 15:53:32 -0700
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Subject: [kernel-hardening] Re: [patch 2/2] fs, proc: Introduce the /proc/<pid>/map_files/
 directory v6
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>, Tejun Heo <tj@kernel.org>, "Kirill A. Shutemov" <kirill@shutemov.name>, containers@lists.osdl.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Nathan Lynch <ntl@pobox.com>, kernel-hardening@lists.openwall.com, Oren Laadan <orenl@cs.columbia.edu>, Daniel Lezcano <dlezcano@fr.ibm.com>, Glauber Costa <glommer@parallels.com>, James Bottomley <jbottomley@parallels.com>, Alexey Dobriyan <adobriyan@gmail.com>, Al Viro <viro@ZenIV.linux.org.uk>, Pavel Emelyanov <xemul@parallels.com>
List-ID: <kernel-hardening.lists.openwall.com>

On Thu, 8 Sep 2011 02:42:34 +0400
Cyrill Gorcunov <gorcunov@gmail.com> wrote:

> > > +err:
> > > +		up_read(&mm->mmap_sem);
> > > +
> > > +		for (i = 0; i < used && !ret; i++) {
> > 
> > The "&& !ret" is unneeded?
> 
> No, it's needed, since it makes sure that if "impossible"
> scenario happens and flex-arrays fails with preallocated
> data so we will reach this point with used > 0 and ret = -ENOMEM
> and thus will not call for proc_map_files_instantiate as needed.

Well, it doesn't need to be tested on each pass around the loop - that's
misleading and inefficient (unless the compiler is being particularly clever).