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

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Message-ID: <202110081401.7AB25E4@keescook>
Date:   Fri, 8 Oct 2021 14:13:09 -0700
From:   Kees Cook <keescook@...omium.org>
To:     David Hildenbrand <david@...hat.com>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        John Hubbard <jhubbard@...dia.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Michal Hocko <mhocko@...e.com>, Pavel Machek <pavel@....cz>,
        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>,
        Vlastimil Babka <vbabka@...e.cz>,
        Johannes Weiner <hannes@...xchg.org>,
        Jonathan Corbet <corbet@....net>,
        Al Viro <viro@...iv.linux.org.uk>,
        Randy Dunlap <rdunlap@...radead.org>,
        Kalesh Singh <kaleshsingh@...gle.com>,
        Peter Xu <peterx@...hat.com>, rppt@...nel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Catalin Marinas <catalin.marinas@....com>,
        vincenzo.frascino@....com,
        Chinwen Chang (張錦文) 
        <chinwen.chang@...iatek.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Jann Horn <jannh@...gle.com>, apopple@...dia.com,
        Yu Zhao <yuzhao@...gle.com>, Will Deacon <will@...nel.org>,
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        Peter Collingbourne <pcc@...gle.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Jens Axboe <axboe@...nel.dk>, legion@...nel.org,
        Rolf Eike Beer <eb@...ix.com>,
        Cyrill Gorcunov <gorcunov@...il.com>,
        Muchun Song <songmuchun@...edance.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Thomas Cedeno <thomascedeno@...gle.com>, sashal@...nel.org,
        cxfcosmos@...il.com, LKML <linux-kernel@...r.kernel.org>,
        linux-fsdevel@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-mm <linux-mm@...ck.org>,
        kernel-team <kernel-team@...roid.com>
Subject: Re: [PATCH v10 3/3] mm: add anonymous vma name refcounting

On Fri, Oct 08, 2021 at 09:43:59AM +0200, David Hildenbrand wrote:
> I'm going to point out that we already do have names for memfds.

I just did the same here[1]. :P

> [...] It's also displayed in /proc/self/maps.

I missed that part! /me screams forever

We really need to filter this at creation time. :( At least
seq_file_path() escapes "\n" for it, but not "\r", so humans on a
terminal could get very confused...

$ ./memfd '^M0000000000000000-ffffffffffffffff rwxp 00000000 00:00 0 [stack]' &
[1] 2953833
$ cat /proc/2953833/maps
...
0000000000000000-ffffffffffffffff rwxp 00000000 00:00 0     [stack] (deleted)
...


-Kees

[1] https://lore.kernel.org/lkml/202110081344.FE6A7A82@keescook

-- 
Kees Cook