This is a note to let you know that I've just added the patch titled
iommu/vt-d: Fix an off-by-one bug in __domain_mapping()
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-vt-d-fix-an-off-by-one-bug-in-__domain_mapping.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From cc4f14aa170d895c9a43bdb56f62070c8a6da908 Mon Sep 17 00:00:00 2001
From: Jiang Liu <[email protected]>
Date: Wed, 26 Nov 2014 09:42:10 +0800
Subject: iommu/vt-d: Fix an off-by-one bug in __domain_mapping()
From: Jiang Liu <[email protected]>
commit cc4f14aa170d895c9a43bdb56f62070c8a6da908 upstream.
There's an off-by-one bug in function __domain_mapping(), which may
trigger the BUG_ON(nr_pages < lvl_pages) when
(nr_pages + 1) & superpage_mask == 0
The issue was introduced by commit 9051aa0268dc "intel-iommu: Combine
domain_pfn_mapping() and domain_sg_mapping()", which sets sg_res to
"nr_pages + 1" to avoid some of the 'sg_res==0' code paths.
It's safe to remove extra "+1" because sg_res is only used to calculate
page size now.
Reported-And-Tested-by: Sudeep Dutt <[email protected]>
Signed-off-by: Jiang Liu <[email protected]>
Acked-By: David Woodhouse <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/iommu/intel-iommu.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1983,7 +1983,7 @@ static int __domain_mapping(struct dmar_
{
struct dma_pte *first_pte = NULL, *pte = NULL;
phys_addr_t uninitialized_var(pteval);
- unsigned long sg_res;
+ unsigned long sg_res = 0;
unsigned int largepage_lvl = 0;
unsigned long lvl_pages = 0;
@@ -1994,10 +1994,8 @@ static int __domain_mapping(struct dmar_
prot &= DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP;
- if (sg)
- sg_res = 0;
- else {
- sg_res = nr_pages + 1;
+ if (!sg) {
+ sg_res = nr_pages;
pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | prot;
}
Patches currently in stable-queue which might be from [email protected]
are
queue-3.18/iommu-vt-d-fix-an-off-by-one-bug-in-__domain_mapping.patch
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