Re: [PATCH 2/2] virtio/virtio_ring: Fix the dma_max_mapping_size call

From: Christoph Hellwig
Date: Mon Jul 22 2019 - 11:27:14 EST


On Mon, Jul 22, 2019 at 04:55:09PM +0200, Eric Auger wrote:
> Do not call dma_max_mapping_size for devices that have no DMA
> mask set, otherwise we can hit a NULL pointer dereference.
>
> This occurs when a virtio-blk-pci device is protected with
> a virtual IOMMU.
>
> Fixes: e6d6dd6c875e ("virtio: Introduce virtio_max_dma_size()")
> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
> Suggested-by: Christoph Hellwig <hch@xxxxxx>

Looks good. virtio maintainers, let me know if you want to queue
it up or if I should pick the patch up through the dma-mapping tree.