linux-kernel - Re: [PATCH v5 10/29] iommufd: Abstract iopt_pin_pages and iopt_unpin

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: <aEHOI522eucrOZyI@Asurada-Nvidia>
Date: Thu, 5 Jun 2025 10:04:35 -0700
From: Nicolin Chen <nicolinc@...dia.com>
To: Jason Gunthorpe <jgg@...dia.com>
CC: <kevin.tian@...el.com>, <corbet@....net>, <will@...nel.org>,
	<bagasdotme@...il.com>, <robin.murphy@....com>, <joro@...tes.org>,
	<thierry.reding@...il.com>, <vdumpa@...dia.com>, <jonathanh@...dia.com>,
	<shuah@...nel.org>, <jsnitsel@...hat.com>, <nathan@...nel.org>,
	<peterz@...radead.org>, <yi.l.liu@...el.com>, <mshavit@...gle.com>,
	<praan@...gle.com>, <zhangzekun11@...wei.com>, <iommu@...ts.linux.dev>,
	<linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-tegra@...r.kernel.org>,
	<linux-kselftest@...r.kernel.org>, <patches@...ts.linux.dev>,
	<mochs@...dia.com>, <alok.a.tiwari@...cle.com>, <vasant.hegde@....com>,
	<dwmw2@...radead.org>, <baolu.lu@...ux.intel.com>
Subject: Re: [PATCH v5 10/29] iommufd: Abstract iopt_pin_pages and
 iopt_unpin_pages helpers

On Thu, Jun 05, 2025 at 12:16:48PM -0300, Jason Gunthorpe wrote:
> On Wed, Jun 04, 2025 at 09:11:07PM -0700, Nicolin Chen wrote:
> 
> > I found the entire ictx would be locked by iommufd_access_create(),
> > then the release fop couldn't even get invoked to destroy objects.
> 
> Yes, that makes sense..
> 
> It looks to me like you can safely leave ictx as NULL instead of
> adding a flag? That would be nicer than leaving a unrefcounted
> pointer floating around..

Hmm, there are a few iommufd_get_object calls using access->ictx
in iommufd_access_attach() and iommufd_access_destroy().

We could have a set of internal access APIs to leave access->ictx
as NULL, as an internal caller has an ictx to pass in. It's going
to be a larger change though..

Thanks
Nicolin