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From: Joerg Roedel <joro@8bytes.org>
To: Vasant Hegde <vasant.hegde@amd.com>
Cc: iommu@lists.linux.dev, robin.murphy@arm.com, will@kernel.org,
	suravee.suthikulpanit@amd.com,
	Matt Fagnani <matt.fagnani@bell.net>
Subject: Re: [PATCH 3/3] iommu/amd: Call BUG_ON in page fault hanlder path if domain is NULL
Date: Fri, 3 Feb 2023 10:36:30 +0100	[thread overview]
Message-ID: <Y9zVnkfEp3bC+UfL@8bytes.org> (raw)
In-Reply-To: <20230113135956.5788-3-vasant.hegde@amd.com>

On Fri, Jan 13, 2023 at 01:59:56PM +0000, Vasant Hegde wrote:
> If IOMMU domain for device group is not setup properly then we may hit
> IOMMU page fault. Current page fault handler assumes that domain is
> always setup and it will hit NULL pointer dereference (see below sample log).
> 
> This is mostly programming error and difficult to recover from here. Hence
> call BUG_ON().

I agree with Robin here, a BUG_ON() is no improvement over a NULL-ptr
dereference. Just handle the domain == NULL case so that this code-path
will not crash.

Thanks,

	Joerg

  parent reply	other threads:[~2023-02-03  9:36 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-13 13:59 [PATCH 1/3] iommu: Attach device group to old domain in error path Vasant Hegde
2023-01-13 13:59 ` [PATCH 2/3] iommu/amd: Skip attach device domain is same as new domain Vasant Hegde
2023-01-13 13:59 ` [PATCH 3/3] iommu/amd: Call BUG_ON in page fault hanlder path if domain is NULL Vasant Hegde
2023-01-13 16:15   ` Robin Murphy
2023-01-17  4:56     ` Vasant Hegde
2023-02-03  9:36   ` Joerg Roedel [this message]
2023-02-03 10:40     ` Vasant Hegde
2023-02-03 11:12       ` Joerg Roedel
2023-02-03 16:52         ` Vasant Hegde
2023-02-01  5:19 ` [PATCH 1/3] iommu: Attach device group to old domain in error path Vasant Hegde

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