From: David Hildenbrand <david@redhat.com>
To: Suren Baghdasaryan <surenb@google.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>,
John Hubbard <jhubbard@nvidia.com>, Pavel Machek <pavel@ucw.cz>,
Colin Cross <ccross@google.com>,
Sumit Semwal <sumit.semwal@linaro.org>,
Dave Hansen <dave.hansen@intel.com>,
Kees Cook <keescook@chromium.org>,
Matthew Wilcox <willy@infradead.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Vlastimil Babka <vbabka@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Al Viro <viro@zeniv.linux.org.uk>,
Randy Dunlap <rdunlap@infradead.org>,
Kalesh Singh <kaleshsingh@google.com>,
Peter Xu <peterx@redhat.com>,
rppt@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
vincenzo.frascino@arm.com,
Chinwen Chang <chinwen.chang@mediatek.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Jann Horn <jannh@google.com>,
apopple@nvidia.com, Yu Zhao <yuzhao@google.com>,
Will Deacon <will@kernel.org>,
fenghua.yu@intel.com, thunder.leizhen@huawei.com,
Hugh Dickins <hughd@google.com>,
feng.tang@intel.com, Jason Gunthorpe <jgg@ziepe.ca>,
Roman Gushchin <guro@fb.com>,
Thomas Gleixner <tglx@linutronix.de>,
krisman@collabora.com, Chris Hyser <chris.hyser@oracle.com>,
Peter Collingbourne <pcc@google.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Jens Axboe <axboe@kernel.dk>,
legion@kernel.org, Rolf Eike Beer <eb@emlix.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Muchun Song <songmuchun@bytedance.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Thomas Cedeno <thomascedeno@google.com>,
sashal@kernel.org, cxfcosmos@gmail.com,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm <linux-mm@kvack.org>,
kernel-team <kernel-team@android.com>,
Tim Murray <timmurray@google.com>
Subject: Re: [PATCH v10 3/3] mm: add anonymous vma name refcounting
Date: Thu, 7 Oct 2021 09:27:39 +0200 [thread overview]
Message-ID: <3645f74d-54b4-9223-1d53-75cade471fad@redhat.com> (raw)
In-Reply-To: <CAJuCfpEZzrN+V2g4+RsRs5v3e60RGvXOCk_X9e3wWkeMBZProg@mail.gmail.com>
On 07.10.21 05:01, Suren Baghdasaryan wrote:
> On Wed, Oct 6, 2021 at 7:53 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>>
>> On Wed, 6 Oct 2021 19:46:57 -0700 Suren Baghdasaryan <surenb@google.com> wrote:
>>
>>>>>>> I wish it was that simple and for some names like [anon:.bss] or
>>>>>>> [anon:dalvik-zygote space] reserving a unique id would work, however
>>>>>>> some names like [anon:dalvik-/system/framework/boot-core-icu4j.art]
>>>>>>> are generated dynamically at runtime and include package name.
>>>>>>
>>>>>> Valuable information
>>>>>
>>>>> Yeah, I should have described it clearer the first time around.
>>>>
>>>> If it gets this fancy then the 80 char limit is likely to become a
>>>> significant limitation and the choice should be explained & justified.
>>>>
>>>> Why not 97? 1034? Why not just strndup_user() and be done with it?
>>>
>>> The original patch from 8 years ago used 256 as the limit but Rasmus
>>> argued that the string content should be human-readable, so 80 chars
>>> seems to be a reasonable limit (see:
>>> https://lore.kernel.org/all/d8619a98-2380-ca96-001e-60fe9c6204a6@rasmusvillemoes.dk),
>>> which makes sense to me. We should be able to handle the 80 char limit
>>> by trimming it before calling prctl().
>>
>> What's the downside to making it unlimited?
>
> If we ignore the human-readability argument, I guess the possibility
> of abuse and increased memory consumption? I'm guessing parsing such a
> string is also easier if there is a known limit?
64k * 80 bytes already makes me nervous enough :)
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-10-07 7:27 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-01 20:56 [PATCH v10 1/3] mm: rearrange madvise code to allow for reuse Suren Baghdasaryan
2021-10-01 20:56 ` [PATCH v10 2/3] mm: add a field to store names for private anonymous memory Suren Baghdasaryan
2021-10-01 23:08 ` Andrew Morton
2021-10-02 0:52 ` Suren Baghdasaryan
2021-10-04 16:21 ` Suren Baghdasaryan
2021-10-07 2:39 ` Andrew Morton
2021-10-07 2:50 ` Suren Baghdasaryan
2021-10-01 20:56 ` [PATCH v10 3/3] mm: add anonymous vma name refcounting Suren Baghdasaryan
2021-10-05 18:42 ` Pavel Machek
2021-10-05 19:14 ` Suren Baghdasaryan
2021-10-05 19:21 ` Kees Cook
2021-10-05 20:04 ` Pavel Machek
2021-10-05 20:43 ` Suren Baghdasaryan
2021-10-06 6:57 ` John Hubbard
2021-10-06 8:27 ` Michal Hocko
2021-10-06 9:27 ` David Hildenbrand
2021-10-06 15:01 ` Suren Baghdasaryan
2021-10-06 15:07 ` David Hildenbrand
2021-10-06 15:20 ` Suren Baghdasaryan
2021-10-07 2:29 ` Andrew Morton
2021-10-07 2:46 ` Suren Baghdasaryan
2021-10-07 2:53 ` Andrew Morton
2021-10-07 3:01 ` Suren Baghdasaryan
2021-10-07 7:27 ` David Hildenbrand [this message]
2021-10-07 7:33 ` David Hildenbrand
2021-10-07 15:42 ` Suren Baghdasaryan
2021-10-06 17:58 ` Pavel Machek
2021-10-06 18:18 ` Suren Baghdasaryan
2021-10-07 8:10 ` Michal Hocko
2021-10-07 8:41 ` Pavel Machek
2021-10-07 8:47 ` Rasmus Villemoes
2021-10-07 10:15 ` Pavel Machek
2021-10-07 16:04 ` Suren Baghdasaryan
2021-10-07 16:40 ` Michal Hocko
2021-10-07 16:58 ` Suren Baghdasaryan
2021-10-07 17:31 ` Michal Hocko
2021-10-07 17:50 ` Suren Baghdasaryan
2021-10-07 18:12 ` Kees Cook
2021-10-07 18:50 ` Suren Baghdasaryan
2021-10-07 19:02 ` John Hubbard
2021-10-07 21:32 ` Suren Baghdasaryan
2021-10-08 1:04 ` Liam Howlett
2021-10-08 7:25 ` Rasmus Villemoes
2021-10-08 7:43 ` David Hildenbrand
2021-10-08 21:13 ` Kees Cook
2021-10-08 6:34 ` Michal Hocko
2021-10-08 14:14 ` Dave Hansen
2021-10-08 14:57 ` Michal Hocko
2021-10-08 16:10 ` Suren Baghdasaryan
2021-10-08 20:58 ` Kees Cook
2021-10-11 8:36 ` Michal Hocko
2021-10-12 1:18 ` Suren Baghdasaryan
2021-10-12 1:20 ` Suren Baghdasaryan
2021-10-12 3:00 ` Johannes Weiner
2021-10-12 5:36 ` Suren Baghdasaryan
2021-10-12 18:26 ` Johannes Weiner
2021-10-12 18:52 ` Suren Baghdasaryan
2021-10-12 20:41 ` Johannes Weiner
2021-10-12 20:59 ` Suren Baghdasaryan
2021-10-12 7:36 ` Michal Hocko
2021-10-12 16:50 ` Suren Baghdasaryan
2021-10-12 7:43 ` David Hildenbrand
2021-10-12 17:01 ` Suren Baghdasaryan
2021-10-14 20:16 ` Suren Baghdasaryan
2021-10-15 8:03 ` David Hildenbrand
2021-10-15 16:30 ` Suren Baghdasaryan
2021-10-15 16:39 ` David Hildenbrand
2021-10-15 18:33 ` Suren Baghdasaryan
2021-10-15 17:45 ` Kees Cook
2021-10-07 7:59 ` Michal Hocko
2021-10-07 15:45 ` Suren Baghdasaryan
2021-10-07 16:37 ` Michal Hocko
2021-10-07 16:43 ` Suren Baghdasaryan
2021-10-07 17:25 ` Michal Hocko
2021-10-07 17:30 ` Suren Baghdasaryan
2021-10-04 7:03 ` [PATCH v10 1/3] mm: rearrange madvise code to allow for reuse Rolf Eike Beer
2021-10-04 16:18 ` Suren Baghdasaryan
2021-10-05 21:00 ` Liam Howlett
2021-10-05 21:30 ` Suren Baghdasaryan
2021-10-06 17:33 ` Liam Howlett
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