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authorJuergen Gross <jgross@suse.com>2019-06-14 07:46:02 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-08-06 18:28:29 +0200
commit430c54323a3fb5286e356a5ec39c740a43fda3b5 (patch)
parente1a785b02384c04c34f535c528bb25fa6bfa9f9e (diff)
xen/swiotlb: fix condition for calling xen_destroy_contiguous_region()
commit 50f6393f9654c561df4cdcf8e6cfba7260143601 upstream. The condition in xen_swiotlb_free_coherent() for deciding whether to call xen_destroy_contiguous_region() is wrong: in case the region to be freed is not contiguous calling xen_destroy_contiguous_region() is the wrong thing to do: it would result in inconsistent mappings of multiple PFNs to the same MFN. This will lead to various strange crashes or data corruption. Instead of calling xen_destroy_contiguous_region() in that case a warning should be issued as that situation should never occur. Cc: stable@vger.kernel.org Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index a8a388382347..80e292227cef 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -365,8 +365,8 @@ xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
/* Convert the size to actually allocated. */
size = 1UL << (order + XEN_PAGE_SHIFT);
- if (((dev_addr + size - 1 <= dma_mask)) ||
- range_straddles_page_boundary(phys, size))
+ if (!WARN_ON((dev_addr + size - 1 > dma_mask) ||
+ range_straddles_page_boundary(phys, size)))
xen_destroy_contiguous_region(phys, order);
xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);