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Commit 50f6393f authored by Juergen Gross's avatar Juergen Gross
Browse files

xen/swiotlb: fix condition for calling xen_destroy_contiguous_region() 



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: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: default avatarJan Beulich <jbeulich@suse.com>
Acked-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent a78d14a3

drivers/xen/swiotlb-xen.c

+2 −2
Original line number Diff line number Diff line
@@ -361,8 +361,8 @@ 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);