This is C standard hair-splitting, but afaict
- sum will be promoted to signed int in computation since
uint8_t fits
- signed overflow is undefined.
No we need to add up an awful lot of bytes to actually make it
overflow. But I guess the real risk is gcc spotting this and going
bananas. Fix this by simply using unsigned in to force all computations
to use the well-defined unsigned behaviour.
Spotted by coverity.
Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxx>
Cc: Jean-Francois Moine <moinejf@xxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/i2c/tda998x_drv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 48af5cac1902..ae2754760d77 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -568,7 +568,7 @@ static irqreturn_t tda998x_irq_thread(int irq, void *data)
static uint8_t tda998x_cksum(uint8_t *buf, size_t bytes)
{
- uint8_t sum = 0;
+ unsigned sum = 0;
while (bytes--)
sum += *buf++;
--
1.8.5.2
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