linux-kernel - Re: [PATCH net-next] page_pool: add debug for release to cache from wrong CPU

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] [day] [month] [year] [list]

Message-ID: <20250923162650.317f2527@kernel.org>
Date: Tue, 23 Sep 2025 16:26:50 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Dragos Tatulea <dtatulea@...dia.com>
Cc: Jesper Dangaard Brouer <hawk@...nel.org>, "David S. Miller"
 <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Paolo Abeni
 <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, Ilias Apalodimas
 <ilias.apalodimas@...aro.org>, Sebastian Andrzej Siewior
 <bigeasy@...utronix.de>, Clark Williams <clrkwllms@...nel.org>, Steven
 Rostedt <rostedt@...dmis.org>, netdev@...r.kernel.org, Tariq Toukan
 <tariqt@...dia.com>, linux-kernel@...r.kernel.org,
 linux-rt-devel@...ts.linux.dev
Subject: Re: [PATCH net-next] page_pool: add debug for release to cache from
 wrong CPU

On Tue, 23 Sep 2025 16:00:27 +0000 Dragos Tatulea wrote:
> > But you get what I'm saying right? I'm questioning whether _rx_napi()
> > flavor of calls even make sense these days. If they don't I'd think
> > the drivers can't be wrong and the need for the debug check is
> > diminished?  
> I got the point for XDP. I am not sure if you are arguing the same thing
> for the other users though. For example. there are many drivers
> releasing netmems with direct=true.

Right, I was thinking that XDP is the only complex case.
The other direct=true cases generally happen on the Rx path
when we are processing the frame. So chances that we get the 
context wrong are much lower. XDP is using the recycling from
Tx completions paths IIUC. So we need far more care in checking
that the frame actually came from the local NAPI.