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From: Joerg Roedel <>
To: Robin Murphy <>
	Prakash Gupta <>
Subject: Re: [PATCH] iommu/iova: Don't BUG on invalid PFNs
Date: Tue, 30 Jun 2020 10:42:51 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Tue, Jun 02, 2020 at 02:08:18PM +0100, Robin Murphy wrote:
> Unlike the other instances which represent a complete loss of
> consistency within the rcache mechanism itself, or a fundamental
> and obvious misconfiguration by an IOMMU driver, the BUG_ON() in
> iova_magazine_free_pfns() can be provoked at more or less any time
> in a "spooky action-at-a-distance" manner by any old device driver
> passing nonsense to dma_unmap_*() which then propagates through to
> queue_iova().
> Not only is this well outside the IOVA layer's control, it's also
> nowhere near fatal enough to justify panicking anyway - all that
> really achieves is to make debugging the offending driver more
> difficult. Let's simply WARN and otherwise ignore bogus PFNs.
> Reported-by: Prakash Gupta <>
> Signed-off-by: Robin Murphy <>
> ---
>  drivers/iommu/iova.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Applied without stable tag, thanks.

iommu mailing list

      parent reply	other threads:[~2020-06-30  8:43 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-02 13:08 [PATCH] iommu/iova: Don't BUG on invalid PFNs Robin Murphy
2020-06-10  9:27 ` guptap
2020-06-10 10:12   ` Robin Murphy
2020-06-30  8:42 ` Joerg Roedel [this message]

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