From: Sasha Levin <sashal@kernel•org>
To: linux-kernel@vger•kernel.org, stable@vger•kernel.org
Cc: Breno Leitao <leitao@debian•org>,
linuxppc-dev@lists•ozlabs.org, Sasha Levin <sashal@kernel•org>
Subject: [PATCH AUTOSEL 4.4 04/40] powerpc/iommu: Avoid derefence before pointer check
Date: Sat, 9 Nov 2019 21:49:56 -0500 [thread overview]
Message-ID: <20191110025032.827-4-sashal@kernel.org> (raw)
In-Reply-To: <20191110025032.827-1-sashal@kernel.org>
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 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
next parent reply other threads:[~2019-11-10 3:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191110025032.827-1-sashal@kernel.org>
2019-11-10 2:49 ` Sasha Levin [this message]
2019-11-10 2:49 ` [PATCH AUTOSEL 4.4 05/40] powerpc/64s/hash: Fix stab_rr off by one initialization Sasha Levin
2019-11-10 2:49 ` [PATCH AUTOSEL 4.4 06/40] powerpc/pseries: Disable CPU hotplug across migrations Sasha Levin
2019-11-10 2:49 ` [PATCH AUTOSEL 4.4 07/40] libfdt: Ensure INT_MAX is defined in libfdt_env.h Sasha Levin
2019-11-10 2:50 ` [PATCH AUTOSEL 4.4 10/40] net: toshiba: fix return type of ndo_start_xmit function Sasha Levin
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