[PATCH AUTOSEL 4.19 014/206] PM / devfreq: tegra30: Fix integer overflow on CPU's freq max out

From: Sasha Levin
Date: Thu Sep 17 2020 - 22:52:04 EST


From: Dmitry Osipenko <digetx@xxxxxxxxx>

[ Upstream commit 53b4b2aeee26f42cde5ff2a16dd0d8590c51a55a ]

There is another kHz-conversion bug in the code, resulting in integer
overflow. Although, this time the resulting value is 4294966296 and it's
close to ULONG_MAX, which is okay in this case.

Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Tested-by: Peter Geis <pgwipeout@xxxxxxxxx>
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/devfreq/tegra-devfreq.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index 06768074d2d82..479d9575e1245 100644
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -80,6 +80,8 @@

#define KHZ 1000

+#define KHZ_MAX (ULONG_MAX / KHZ)
+
/* Assume that the bus is saturated if the utilization is 25% */
#define BUS_SATURATION_RATIO 25

@@ -180,7 +182,7 @@ struct tegra_actmon_emc_ratio {
};

static struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
- { 1400000, ULONG_MAX },
+ { 1400000, KHZ_MAX },
{ 1200000, 750000 },
{ 1100000, 600000 },
{ 1000000, 500000 },
--
2.25.1