linux-kernel - Re: [PATCH v5 03/13] iommufd: Add iommufd_verify_unfinalized

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: <20241030125349.GE6956@nvidia.com>
Date: Wed, 30 Oct 2024 09:53:49 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Nicolin Chen <nicolinc@...dia.com>
Cc: kevin.tian@...el.com, will@...nel.org, joro@...tes.org,
	suravee.suthikulpanit@....com, robin.murphy@....com,
	dwmw2@...radead.org, baolu.lu@...ux.intel.com, shuah@...nel.org,
	linux-kernel@...r.kernel.org, iommu@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-kselftest@...r.kernel.org, eric.auger@...hat.com,
	jean-philippe@...aro.org, mdf@...nel.org, mshavit@...gle.com,
	shameerali.kolothum.thodi@...wei.com, smostafa@...gle.com,
	yi.l.liu@...el.com, aik@....com, zhangfei.gao@...aro.org,
	patches@...ts.linux.dev
Subject: Re: [PATCH v5 03/13] iommufd: Add iommufd_verify_unfinalized_object

On Tue, Oct 29, 2024 at 09:05:14PM -0700, Nicolin Chen wrote:
> On Tue, Oct 29, 2024 at 03:55:58PM -0300, Jason Gunthorpe wrote:
> > On Tue, Oct 29, 2024 at 09:18:05AM -0700, Nicolin Chen wrote:
> > > I think we'd need the same change in iommufd_object_abort() too.
> > 
> > Makes sense
> 
> I found xa_cmpxchg() does xas_result to its returning value, which
> turns XA_ZERO_ENTRY into NULL failing our intended verifications.

Oh.. that is annoying, you can't actually tell if cmpxchg failed :\
NULL means success if it was XA_ZERO_ENTRY and failure of it was not
populated! Hmm, I might ask Matthew about this

Your version looks OK

Jason