Messages in this thread | | | Date | Wed, 10 Jun 2020 14:57:00 +0530 | From | guptap@codeauro ... | Subject | Re: [PATCH] iommu/iova: Don't BUG on invalid PFNs |
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On 2020-06-02 18:38, 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 <guptap@codeaurora.org> > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > drivers/iommu/iova.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) >
Copying stable@vger.kernel.org
You can add Reviewed-by: Prakash Gupta <guptap@codeaurora.org>
> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 0e6a9536eca6..612cbf668adf 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -811,7 +811,9 @@ iova_magazine_free_pfns(struct iova_magazine *mag, > struct iova_domain *iovad) > for (i = 0 ; i < mag->size; ++i) { > struct iova *iova = private_find_iova(iovad, mag->pfns[i]); > > - BUG_ON(!iova); > + if (WARN_ON(!iova)) > + continue; > + > private_free_iova(iovad, iova); > }
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