linux-kernel - Re: [PATCH v10 3/3] mm: add anonymous vma name refcounting

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Date:   Mon, 11 Oct 2021 10:36:03 +0200
From:   Michal Hocko <mhocko@...e.com>
To:     Kees Cook <keescook@...omium.org>
Cc:     Suren Baghdasaryan <surenb@...gle.com>,
        Pavel Machek <pavel@....cz>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        David Hildenbrand <david@...hat.com>,
        John Hubbard <jhubbard@...dia.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Colin Cross <ccross@...gle.com>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Dave Hansen <dave.hansen@...el.com>,
        Matthew Wilcox <willy@...radead.org>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
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        Johannes Weiner <hannes@...xchg.org>,
        Jonathan Corbet <corbet@....net>,
        Al Viro <viro@...iv.linux.org.uk>,
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        kernel-team <kernel-team@...roid.com>
Subject: Re: [PATCH v10 3/3] mm: add anonymous vma name refcounting

On Fri 08-10-21 13:58:01, Kees Cook wrote:
> - Strings for "anon" specifically have no required format (this is good)
>   it's informational like the task_struct::comm and can (roughly)
>   anything. There's no naming convention for memfds, AF_UNIX, etc. Why
>   is one needed here? That seems like a completely unreasonable
>   requirement.

I might be misreading the justification for the feature. Patch 2 is
talking about tools that need to understand memeory usage to make
further actions. Also Suren was suggesting "numbering convetion" as an
argument against. 

So can we get a clear example how is this being used actually? If this
is just to be used to debug by humans than I can see an argument for
human readable form. If this is, however, meant to be used by tools to
make some actions then the argument for strings is much weaker.
-- 
Michal Hocko
SUSE Labs