@@ -82,8 +82,15 @@ static void vivid_cec_pin_adap_events(struct cec_adapter *adap, ktime_t ts,
if (adap == NULL)
return;
- ts = ktime_sub_us(ts, (CEC_TIM_START_BIT_TOTAL +
- len * 10 * CEC_TIM_DATA_BIT_TOTAL));
+
+ /*
+ * Suffix ULL on constant 10 makes the expression
+ * CEC_TIM_START_BIT_TOTAL + 10ULL * len * CEC_TIM_DATA_BIT_TOTAL
+ * to be evaluated using 64-bit unsigned arithmetic (u64), which
+ * is what ktime_sub_us expects as second argument.
+ */
+ ts = ktime_sub_us(ts, CEC_TIM_START_BIT_TOTAL +
+ 10ULL * len * CEC_TIM_DATA_BIT_TOTAL);
cec_queue_pin_cec_event(adap, false, ts);
ts = ktime_add_us(ts, CEC_TIM_START_BIT_LOW);
cec_queue_pin_cec_event(adap, true, ts);
Add suffix ULL to constant 10 in order to give the compiler complete information about the proper arithmetic to use. Notice that this constant is used in a context that expects an expression of type u64 (64 bits, unsigned). The expression len * 10 * CEC_TIM_DATA_BIT_TOTAL is currently being evaluated using 32-bit arithmetic. Also, remove unnecessary parentheses and add a code comment to make it clear what is the reason of the code change. Addresses-Coverity-ID: 1454996 ("Unintentional integer overflow") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- Changes in v2: - Update subject and changelog to better reflect the proposed code changes. - Add suffix ULL to constant instead of casting a variable. - Remove unnecessary parentheses. - Add code comment. Changes in v3: - Mention the specific Coverity report in the commit message. drivers/media/platform/vivid/vivid-cec.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)