From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
stable@vger.kernel.org
Subject: [PATCH v3 1/3] xen/swiotlb: fix condition for calling xen_destroy_contiguous_region()
Date: Fri, 14 Jun 2019 07:46:02 +0200 [thread overview]
Message-ID: <20190614054604.30101-2-jgross@suse.com> (raw)
In-Reply-To: <20190614054604.30101-1-jgross@suse.com>
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>
---
V2: always issue a warning in case xen_destroy_contiguous_region()
isn't called (Jan Beulich)
---
drivers/xen/swiotlb-xen.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index d53f3493a6b9..50fd7de54969 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -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);
--
2.16.4
next prev parent reply other threads:[~2019-06-14 5:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-14 5:46 [PATCH v3 0/3] xen/swiotlb: fix an issue and improve swiotlb-xen Juergen Gross
2019-06-14 5:46 ` Juergen Gross [this message]
2019-06-14 5:46 ` [PATCH v3 2/3] xen/swiotlb: simplify range_straddles_page_boundary() Juergen Gross
2019-06-14 5:46 ` [PATCH v3 3/3] xen/swiotlb: remember having called xen_create_contiguous_region() Juergen Gross
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