From: Jason Gunthorpe <jgg@ziepe.ca>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Hector Martin <marcan@marcan.st>, Sven Peter <sven@svenpeter.dev>,
Alyssa Rosenzweig <alyssa@rosenzweig.io>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>, Janne Grunau <j@jannau.net>,
asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
iommu@lists.linux.dev, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] iommu/dart: Fix return code in apple_dart_domain_alloc_paging()
Date: Tue, 31 Oct 2023 21:47:47 -0300 [thread overview]
Message-ID: <20231101004747.GK691768@ziepe.ca> (raw)
In-Reply-To: <20231030123823.GD691768@ziepe.ca>
On Mon, Oct 30, 2023 at 09:38:23AM -0300, Jason Gunthorpe wrote:
> On Mon, Oct 30, 2023 at 03:00:56PM +0300, Dan Carpenter wrote:
> > On Mon, Oct 30, 2023 at 08:56:50AM -0300, Jason Gunthorpe wrote:
> > > On Mon, Oct 30, 2023 at 12:03:12PM +0300, Dan Carpenter wrote:
> > > > The apple_dart_domain_alloc_paging() function is supposed to return NULL
> > > > on error. Returning an error pointer will lead to an Oops in
> > > > __iommu_domain_alloc().
> > > >
> > > > Fixes: 482feb5c6492 ("iommu/dart: Call apple_dart_finalize_domain() as part of alloc_paging()")
> > > > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > > > ---
> > > > drivers/iommu/apple-dart.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> > >
> > > Really need to fix this so the function does return ERR_PTR..
> >
> > It's called as a function pointer. Changing that will create a
> > backporting hazard unless we rename the pointer or something.
>
> You can make that argument about almost any change in the kernel..
>
> IMHO we needed an annotation like __user/__iomem/etc to indicate
> ERR_PTR so at least there is some hope of trivially finding it.
I was thinking about this some more, I think I prefer we fix the core
code to accept the ERR_PTR and just start moving gently in that
direction. I was working on some other stuff and it is starting to get
really confusing that only this op is different.
I'll send a patch
Jason
prev parent reply other threads:[~2023-11-01 0:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-30 9:03 [PATCH] iommu/dart: Fix return code in apple_dart_domain_alloc_paging() Dan Carpenter
2023-10-30 11:56 ` Jason Gunthorpe
2023-10-30 12:00 ` Dan Carpenter
2023-10-30 12:38 ` Jason Gunthorpe
2023-11-01 0:47 ` Jason Gunthorpe [this message]
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