[PATCH v3] ARM: dma-mapping: fix potential uninitialized return

From: Nathan Jones <nathanj439@gmail.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Nathan Jones <nathanj439@gmail.com>
Subject: [PATCH v3] ARM: dma-mapping: fix potential uninitialized return
Date: Fri, 30 Nov 2018 08:07:13 -0500	[thread overview]
Message-ID: <20181130130712.1307-1-nathanj439@gmail.com> (raw)
In-Reply-To: <20181128185910.5778-1-nathanj439@gmail.com>

While trying to use the dma_mmap_*() interface, it was noticed that this
interface returns strange values when passed an incorrect length.

If neither of the if() statements fire then the return value is
uninitialized. In the worst case it returns 0 which means the caller
will think the function succeeded.

Fixes: 1655cf8829d8 ("ARM: dma-mapping: Remove traces of NOMMU code")
Signed-off-by: Nathan Jones <nathanj439@gmail.com>
Acked-by: Vladimir Murzin <vladimir.murzin@arm.com>
---
 arch/arm/mm/dma-mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 661fe48ab78d..78de138aa66d 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -829,7 +829,7 @@ static int __arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 		 void *cpu_addr, dma_addr_t dma_addr, size_t size,
 		 unsigned long attrs)
 {
-	int ret;
+	int ret = -ENXIO;
 	unsigned long nr_vma_pages = vma_pages(vma);
 	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	unsigned long pfn = dma_to_pfn(dev, dma_addr);
-- 
2.19.1


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