linux-kernel - Re: [RFC mm v4 1/2] page_pool: check if nmdesc->pp is !NULL to confirm its usage as pp for net

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: <20251028183356.29601348@kernel.org>
Date: Tue, 28 Oct 2025 18:33:56 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Byungchul Park <byungchul@...com>
Cc: linux-mm@...ck.org, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org, kernel_team@...ynix.com,
 harry.yoo@...cle.com, ast@...nel.org, daniel@...earbox.net,
 davem@...emloft.net, hawk@...nel.org, john.fastabend@...il.com,
 sdf@...ichev.me, saeedm@...dia.com, leon@...nel.org, tariqt@...dia.com,
 mbloch@...dia.com, andrew+netdev@...n.ch, edumazet@...gle.com,
 pabeni@...hat.com, akpm@...ux-foundation.org, david@...hat.com,
 lorenzo.stoakes@...cle.com, Liam.Howlett@...cle.com, vbabka@...e.cz,
 rppt@...nel.org, surenb@...gle.com, mhocko@...e.com, horms@...nel.org,
 jackmanb@...gle.com, hannes@...xchg.org, ziy@...dia.com,
 ilias.apalodimas@...aro.org, willy@...radead.org, brauner@...nel.org,
 kas@...nel.org, yuzhao@...gle.com, usamaarif642@...il.com,
 baolin.wang@...ux.alibaba.com, almasrymina@...gle.com, toke@...hat.com,
 asml.silence@...il.com, bpf@...r.kernel.org, linux-rdma@...r.kernel.org,
 sfr@...b.auug.org.au, dw@...idwei.uk, ap420073@...il.com,
 dtatulea@...dia.com
Subject: Re: [RFC mm v4 1/2] page_pool: check if nmdesc->pp is !NULL to
 confirm its usage as pp for net_iov

On Thu, 23 Oct 2025 16:44:09 +0900 Byungchul Park wrote:
> As a preparation, the check for net_iov, that is not page-backed, should
> avoid using ->pp_magic since net_iov doens't have to do with page type.

doesn't

> Instead, nmdesc->pp can be used if a net_iov or its nmdesc belongs to a
> page pool, by making sure nmdesc->pp is NULL otherwise.

Please explain in the commit message why the new branch in
netmem_is_pp() is necessary. We used to identify the pages based
on PP_SIGNATURE, now we identify them based on page_type.