>On Tue, May 17, 2016 at 01:00:46PM +0100, Colin King wrote:
>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>
>> When CONFIG_DMA_ENGINE_RAID is defined, unmap_pool[] is just 1
>> element in size, however, allows orders of 2..8 to access
>> outside unmap_pool and returns an invalid address. Ensure
>> we fall into the default path and report a BUG() when
>> CONFIG_DMA_ENGINE_RAID is defined and order is out of range.
>>
>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>> ---
>> drivers/dma/dmaengine.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
>> index 8c9f45f..6027e66 100644
>> --- a/drivers/dma/dmaengine.c
>> +++ b/drivers/dma/dmaengine.c
>> @@ -1100,12 +1100,14 @@ static struct dmaengine_unmap_pool
*__get_unmap_pool(int nr)
>> switch (order) {
>> case 0 ... 1:
>> return &unmap_pool[0];
>> + #if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
>Okay if CONFIG_DMA_ENGINE_RAID is enabled (m or y) then IS_ENABLED
>return 1, so we will go inside and not fall into default. And I though
>by changelog that you want it to go to default in CONFIG_DMA_ENGINE_RAID
>is defined!
>What did I miss...
Here it should be when CONFIG_DMA_ENGINE_RAID is NOT defined,
unmap_pool[] is just 1
element in size, and the function "__get_unmap_pool" will access
outside of the array unmap_pool[]
in case orders of 2..8 and returns an invalid address, and I encountered
the issue.
I think the patch is needed to avoid visiting outside of the array
unmap_pool[] if CONFIG_DMA_ENGINE_RAID is NOT defined.
Thanks
Xulin
>> case 2 ... 4:
>> return &unmap_pool[1];
>> case 5 ... 7:
>> return &unmap_pool[2];
>> case 8:
>> return &unmap_pool[3];
>> + #endif
>> default:
>> BUG();
>> return NULL;
>> --
>> 2.8.1
>>
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