linux-kernel - RE: [PATCH] udmabuf: revert 'Add support for mapping hugepages (v4)'

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]

Date:   Tue, 13 Jun 2023 12:25:03 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     "'Kasireddy, Vivek'" <vivek.kasireddy@...el.com>,
        David Hildenbrand <david@...hat.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "qemu-devel@...gnu.org" <qemu-devel@...gnu.org>,
        Hugh Dickins <hughd@...gle.com>
CC:     Gerd Hoffmann <kraxel@...hat.com>,
        "Kim, Dongwon" <dongwon.kim@...el.com>,
        "Chang, Junxiao" <junxiao.chang@...el.com>,
        "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
        "Hocko, Michal" <mhocko@...e.com>,
        "jmarchan@...hat.com" <jmarchan@...hat.com>,
        "muchun.song@...ux.dev" <muchun.song@...ux.dev>,
        James Houghton <jthoughton@...gle.com>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH] udmabuf: revert 'Add support for mapping hugepages (v4)'

From: Kasireddy, Vivek <vivek.kasireddy@...el.com>
> Sent: 13 June 2023 09:26
...
> > Is my understanding correct, that we can effectively long-term pin
> > (worse than mlock) 64 MiB per UDMABUF_CREATE, allowing eventually !root
> > users
>
> The 64 MiB limit is the theoretical upper bound that we have not seen hit in
> practice. Typically, for a 1920x1080 resolution (commonly used in Guests),
> the size of the FB is ~8 MB (1920x1080x4). And, most modern Graphics
> compositors flip between two FBs.

What code does and what potentially malicious code might do
are entirely different things.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)