| From 31b150d50693dd7653dd5c39ee3aad3ef764e156 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 21 Aug 2018 15:44:48 -0300 |
| Subject: powerpc/iommu: Avoid derefence before pointer check |
| |
| From: Breno Leitao <leitao@debian.org> |
| |
| [ Upstream commit 984ecdd68de0fa1f63ce205d6c19ef5a7bc67b40 ] |
| |
| The tbl pointer is being derefenced by IOMMU_PAGE_SIZE prior the check |
| if it is not NULL. |
| |
| Just moving the dereference code to after the check, where there will |
| be guarantee that 'tbl' will not be NULL. |
| |
| Signed-off-by: Breno Leitao <leitao@debian.org> |
| Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/powerpc/kernel/iommu.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c |
| index 19b4c628f3bec..f0dc680e659af 100644 |
| --- a/arch/powerpc/kernel/iommu.c |
| +++ b/arch/powerpc/kernel/iommu.c |
| @@ -785,9 +785,9 @@ dma_addr_t iommu_map_page(struct device *dev, struct iommu_table *tbl, |
| |
| vaddr = page_address(page) + offset; |
| uaddr = (unsigned long)vaddr; |
| - npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl)); |
| |
| if (tbl) { |
| + npages = iommu_num_pages(uaddr, size, IOMMU_PAGE_SIZE(tbl)); |
| align = 0; |
| if (tbl->it_page_shift < PAGE_SHIFT && size >= PAGE_SIZE && |
| ((unsigned long)vaddr & ~PAGE_MASK) == 0) |
| -- |
| 2.20.1 |
| |
