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Date: Mon, 25 Nov 2024 08:59:12 +0100
From: Christoph Hellwig <hch@lst.de>
To: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>,
	Michael Kelley <mikelley@microsoft.com>,
	Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>, iommu@lists.linux.dev,
	linux-kernel@vger.kernel.org, Raphael Isemann <teemperor@gmail.com>,
	Cristiano Giuffrida <giuffrida@cs.vu.nl>,
	Herbert Bos <h.j.bos@vu.nl>, Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [RFC 1/1] swiotlb: Replace BUG_ON() with graceful error
 handling
Message-ID: <20241125075912.GA16480@lst.de>
References: <20241122191304.4182642-1-bjohannesmeyer@gmail.com> <20241122191304.4182642-2-bjohannesmeyer@gmail.com>
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On Fri, Nov 22, 2024 at 08:13:04PM +0100, Brian Johannesmeyer wrote:
> Replace the BUG_ON() assertion in swiotlb_release_slots() with a
> conditional check and return. This change prevents a corrupted tlb_addr
> from causing a kernel panic.

We'll at least want a WARN_ON_ONCE here.  But what is the threat model
here?  The tlb_addr is handed out by swiotlb and should not be modified
by the driver.