lkml.org 
[lkml]   [2019]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH AUTOSEL 4.19 026/191] powerpc/iommu: Avoid derefence before pointer check
Date
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
\
 
 \ /
  Last update: 2019-11-10 03:41    [W:0.736 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site