From: Jason Gunthorpe <jgg@nvidia.com>
To: Hans Verkuil <hverkuil+cisco@kernel.org>
Cc: iommu@lists.linux.dev,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Subject: Re: [PATCH] iommu: __iommu_attach_group: check for non-NULL blocking_domain
Date: Mon, 29 Sep 2025 10:02:14 -0300 [thread overview]
Message-ID: <20250929130214.GK2617119@nvidia.com> (raw)
In-Reply-To: <58aabb55-0030-49df-81ed-d4a68174b57e@kernel.org>
On Mon, Sep 29, 2025 at 02:18:50PM +0200, Hans Verkuil wrote:
> On 29/09/2025 14:07, Jason Gunthorpe wrote:
> > On Mon, Sep 29, 2025 at 10:23:47AM +0200, Hans Verkuil wrote:
> >
> >> Since I am unfamiliar with the iommu core code, I am uncertain whether I am
> >> just papering over a bug elsewhere, or whether this is really the correct solution.
> >
> > It is papering over something, group->domain is not supposed to be
> > NULL at this point.. That probably means the iommu driver has not been
>
> It's group->blocking_domain that's NULL, not group->domain.
Er, I thought you were hitting a false positive on this:
group->domain != group->blocking_domain
ie NULL != NULL
But I suppose the whole expression is checking for group->domain
already.
All your patch does is entirely disable the safetly logic :\
What is isp_attach_iommu() trying to accomplish? It does
arm_iommu_detach_device() and then arm_iommu_attach_device() ?
Why?
Is this trying to force a non-identity translation for ISP?
Jason
next prev parent reply other threads:[~2025-09-29 13:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-29 8:23 [PATCH] iommu: __iommu_attach_group: check for non-NULL blocking_domain Hans Verkuil
2025-09-29 12:07 ` Jason Gunthorpe
2025-09-29 12:18 ` Hans Verkuil
2025-09-29 13:02 ` Jason Gunthorpe [this message]
2025-09-29 13:30 ` Hans Verkuil
2025-09-29 13:53 ` Jason Gunthorpe
2025-09-30 10:28 ` Robin Murphy
2025-10-01 6:03 ` Sakari Ailus
2025-10-01 15:44 ` Jason Gunthorpe
2025-10-07 9:38 ` Hans Verkuil
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