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Message-Id: <20191110025032.827-4-sashal@kernel.org>
Date: Sat, 9 Nov 2019 21:49:56 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Breno Leitao <leitao@...ian.org>,
Michael Ellerman <mpe@...erman.id.au>,
Sasha Levin <sashal@...nel.org>, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH AUTOSEL 4.4 04/40] powerpc/iommu: Avoid derefence before pointer check
From: Breno Leitao <leitao@...ian.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@...ian.org>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Sasha Levin <sashal@...nel.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 a8e3490b54e3b..4c9b5970af371 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -764,9 +764,9 @@ 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
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