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iommu/vt-d: fix memory leakage caused by commit ea8ea46 

Commit ea8ea46 "iommu/vt-d: Clean up and fix page table clear/free
behaviour" introduces possible leakage of DMA page tables due to:
        for (pte = page_address(pg); !first_pte_in_page(pte); pte++) {
                if (dma_pte_present(pte) && !dma_pte_superpage(pte))
                        freelist = dma_pte_list_pagetables(domain, level - 1,
                                                           pte, freelist);
        }

For the first pte in a page, first_pte_in_page(pte) will always be true,
thus dma_pte_list_pagetables() will never be called and leak DMA page
tables if level is bigger than 1.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Jiang Liu 2014-04-09 10:20:39 +08:00 committed by David Woodhouse
parent 7713ec066a
commit adeb25905c
1 changed files with 4 additions and 2 deletions
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6
drivers/iommu/intel-iommu.c
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@ -1009,11 +1009,13 @@ static struct page *dma_pte_list_pagetables(struct dmar_domain *domain,
if (level == 1)
return freelist;
for (pte = page_address(pg); !first_pte_in_page(pte); pte++) {
pte = page_address(pg);
do {
if (dma_pte_present(pte) && !dma_pte_superpage(pte))
freelist = dma_pte_list_pagetables(domain, level - 1,
pte, freelist);
}
pte++;
} while (!first_pte_in_page(pte));
return freelist;
}