From: David Hildenbrand <david@redhat.com>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, linux-mm@kvack.org,
linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Yi Lai <yi1.lai@intel.com>,
pbonzini@redhat.com, seanjc@google.com, tabba@google.com,
jackmanb@google.com, yosryahmed@google.com, jannh@google.com,
rppt@kernel.org
Subject: Re: [PATCH bpf] lib/buildid: handle memfd_secret() files in build_id_parse()
Date: Thu, 17 Oct 2024 19:41:29 +0200 [thread overview]
Message-ID: <7ce32d37-18ef-493d-a698-42ee8a7421ab@redhat.com> (raw)
In-Reply-To: <d62whv7kff5yshsyzkykgxpgfycfivygyhlqwifvudnj5adun7@kqd6hcsbmee6>
On 17.10.24 18:22, Shakeel Butt wrote:
> On Thu, Oct 17, 2024 at 11:17:19AM GMT, David Hildenbrand wrote:
>> On 16.10.24 20:39, Shakeel Butt wrote:
>>> Ccing couple more folks who are doing similar work (ASI, guest_memfd)
>>>
>>> Folks, what is the generic way to check if a given mapping has folios
>>> unmapped from kernel address space?
>>
>>
>> Can't we just lookup the mapping and refuse these folios that really
>> shouldn't be looked at?
>>
>> See gup_fast_folio_allowed() where we refuse secretmem_mapping().
>
> That is exactly what this patch is doing. See [1].
Hah! I should have looked at the full patch not just the discussion
where I was CCed :)
> The reason I asked
> this question was because I see parallel efforts related to guest_memfd
> and ASI are going to unmap folios from direct map. (Yosry already
> explained ASI is a bit different). We want a more robust and future
> proof solution.
There was a discussion a while ago about having the abstraction of
inaccessible mappings.
See
https://lore.kernel.org/all/c87a4ba0-b9c4-4044-b0c3-c1112601494f@redhat.com/
It would be a more future-proof replacement of the secretmem checks.
--
Cheers,
David / dhildenb
prev parent reply other threads:[~2024-10-17 17:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-14 23:56 Andrii Nakryiko
2024-10-15 0:00 ` Shakeel Butt
2024-10-16 18:39 ` Shakeel Butt
2024-10-16 19:59 ` Yosry Ahmed
2024-10-16 21:45 ` Shakeel Butt
2024-10-17 9:17 ` David Hildenbrand
2024-10-17 16:22 ` Shakeel Butt
2024-10-17 17:41 ` David Hildenbrand [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7ce32d37-18ef-493d-a698-42ee8a7421ab@redhat.com \
--to=david@redhat.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=jackmanb@google.com \
--cc=jannh@google.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=martin.lau@kernel.org \
--cc=pbonzini@redhat.com \
--cc=rppt@kernel.org \
--cc=seanjc@google.com \
--cc=shakeel.butt@linux.dev \
--cc=tabba@google.com \
--cc=yi1.lai@intel.com \
--cc=yosryahmed@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox