linux-kernel - Re: [RFC][PATCH] uprobe: support for private hugetlb mappings

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b70a3d3a-ea8b-4b20-964b-b019c146945a@redhat.com>
Date: Mon, 22 Apr 2024 11:39:33 +0200
From: David Hildenbrand <david@...hat.com>
To: Guillaume Morin <guillaume@...infr.org>,
 Mike Kravetz <mike.kravetz@...cle.com>, oleg@...hat.com,
 linux-kernel@...r.kernel.org
Subject: Re: [RFC][PATCH] uprobe: support for private hugetlb mappings

On 19.04.24 20:37, Guillaume Morin wrote:
> libhugetlbfs, the Intel iodlr code both allow to remap .text onto a
> hugetlb private mapping. It's also pretty easy to do it manually.
> One drawback of using this functionality is the lack of support for
> uprobes (NOTE uprobe ignores shareable vmas)
> 
> This patch adds support for private hugetlb mappings.  It does require exposing
> some hugetlbfs innards and relies on copy_user_large_folio which is only
> available when CONFIG_HUGETLBFS is used so I had to use an ugly #ifdef
> 
> If there is some interest in applying this patch in some form or
> another, I am open to any refactoring suggestions (esp getting rid the
> #ifdef in uprobes.c) . I tried to limit the
> amount of branching.

All that hugetlb special casing .... oh my. What's the benefit why we 
should be interested in making that code less clean -- to phrase it in a 
nice way ;) ?

Yes, libhugetlbfs exists. But why do we have to support uprobes with it? 
Nobody cared until now, why care now?

-- 
Cheers,

David / dhildenb