From: Juergen Gross Date: Fri, 14 Jun 2019 05:46:02 +0000 (+0200) Subject: xen/swiotlb: fix condition for calling xen_destroy_contiguous_region() X-Git-Tag: v4.4.188~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=430c54323a3fb5286e356a5ec39c740a43fda3b5;p=thirdparty%2Fkernel%2Fstable.git 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 Reviewed-by: Boris Ostrovsky Reviewed-by: Jan Beulich Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index a8a3883823476..80e292227cefe 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);