From: Jason Gunthorpe <jgg@ziepe.ca>
To: Peiyang He <peiyang_he@smail.nju.edu.cn>
Cc: kevin.tian@intel.com, joro@8bytes.org, will@kernel.org,
robin.murphy@arm.com, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, syzkaller@googlegroups.com
Subject: Re: [BUG] iommufd: dma-buf-backed iopt_pages wrongly reaches userspace GUP path and triggers lockdep warning
Date: Wed, 8 Jul 2026 11:36:09 -0300 [thread overview]
Message-ID: <20260708143609.GI118978@ziepe.ca> (raw)
In-Reply-To: <E8540D7D05768C91+8b2ef227-3368-494e-909d-7b28e1489dfb@smail.nju.edu.cn>
On Wed, Jul 08, 2026 at 06:44:25PM +0800, Peiyang He wrote:
> =============
> Suggested fix
> =============
>
> If above analysis is correct, we should add dma-buf rejection in iopt_area_add_access()
> or/and iommufd_access_pin_pages(), similar to iopt_pages_rw_access().
Yes, this is right, it is definitely a meaningful bug that DMABUF is
not blocked from access. Do you want to send a patch?
Jason
next prev parent reply other threads:[~2026-07-08 14:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-08 10:44 [BUG] iommufd: dma-buf-backed iopt_pages wrongly reaches userspace GUP path and triggers lockdep warning Peiyang He
2026-07-08 14:36 ` Jason Gunthorpe [this message]
2026-07-09 2:58 ` Peiyang He
2026-07-09 5:08 ` [PATCH] iommufd: Reject DMABUF pages from the access pin path Peiyang He
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