Messages in this thread Patch in this message | | | From | Huibin Hong <> | Subject | [PATCH] watchdog: dw_wdt: fix overflow issue in dw_wdt_top_in_seconds | Date | Thu, 27 Jul 2017 20:50:43 +0800 |
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If top is 15, (1 << (16 + top)) may be negative.
Change-Id: I76e4a603a54f093e64a4b266008570e3afcdb35a Signed-off-by: Huibin Hong <huibin.hong@rock-chips.com> --- drivers/watchdog/dw_wdt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c index 6ea0634..059c974 100644 --- a/drivers/watchdog/dw_wdt.c +++ b/drivers/watchdog/dw_wdt.c @@ -81,7 +81,9 @@ static inline int dw_wdt_top_in_seconds(unsigned top) * There are 16 possible timeout values in 0..15 where the number of * cycles is 2 ^ (16 + i) and the watchdog counts down. */ - return (1 << (16 + top)) / clk_get_rate(dw_wdt.clk); + unsigned int cycles = 1 << (16 + top); + + return cycles / clk_get_rate(dw_wdt.clk); } static int dw_wdt_get_top(void) -- 1.9.1
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