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[PATCH][V2] dmaengine: coh901318: fix integer overflow when shifting more than 32 places

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  [PATCH][V2] dmaengine: coh901318: fix integer overflow when shifting more than 32 places Colin King <colin.king@canonical.com> - 2016-09-29 20:20 +0200
    Re: [PATCH][V2] dmaengine: coh901318: fix integer overflow when  shifting more than 32 places Vinod Koul <vinod.koul@intel.com> - 2016-09-30 19:50 +0200

#1493647 — [PATCH][V2] dmaengine: coh901318: fix integer overflow when shifting more than 32 places

From: Colin Ian King <colin.king@canonical.com>

Currently U300_DMA_CHANNELS is set to 40, meaning that the shift of 1 can
be more than 32 places, which leads to a 32 bit integer overflow. Fix this
by using 1ULL instead of 1 before shifting it.  Also add braces on the
for-loop to keep with coding style conventions.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/dma/coh901318.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index 2835f3e..74794c9 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -1352,9 +1352,10 @@ static ssize_t coh901318_debugfs_read(struct file *file, char __user *buf,
 
 	tmp += sprintf(tmp, "DMA -- enabled dma channels\n");
 
-	for (i = 0; i < U300_DMA_CHANNELS; i++)
-		if (started_channels & (1 << i))
+	for (i = 0; i < U300_DMA_CHANNELS; i++) {
+		if (started_channels & (1ULL << i))
 			tmp += sprintf(tmp, "channel %d\n", i);
+	}
 
 	tmp += sprintf(tmp, "Pool alloc nbr %d\n", pool_count);
 
-- 
2.9.3

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#1494221 — Re: [PATCH][V2] dmaengine: coh901318: fix integer overflow when shifting more than 32 places

On Thu, Sep 29, 2016 at 07:14:38PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently U300_DMA_CHANNELS is set to 40, meaning that the shift of 1 can
> be more than 32 places, which leads to a 32 bit integer overflow. Fix this
> by using 1ULL instead of 1 before shifting it.  Also add braces on the
> for-loop to keep with coding style conventions.

Applied, thanks

-- 
~Vinod

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