16.07.2019 15:30, Chanwoo Choi пишет: > On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote: >> Potentially very high boosting could cause an integer overflow for a >> highly clocked memory after conversion to MHz. >> >> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> >> --- >> drivers/devfreq/tegra30-devfreq.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c >> index 2f59c78930bd..0de1efdaabf4 100644 >> --- a/drivers/devfreq/tegra30-devfreq.c >> +++ b/drivers/devfreq/tegra30-devfreq.c >> @@ -460,6 +460,7 @@ static unsigned long actmon_update_target(struct tegra_devfreq *tegra, >> unsigned long target_freq; >> >> target_freq = dev->avg_count / ACTMON_SAMPLING_PERIOD + dev->boost_freq; >> + target_freq = min(target_freq, ULONG_MAX / KHZ); > > Did you meet this corner case? I can't recall that, technically it could happen and I don't feel comfortable by having potential integer overflows anyway. > If have to change it, you better to use 'tegra->max_freq' as following: > min(target_freq, tegra->max_freq); The 'tegra->max_freq' will work here, but 'ULONG_MAX / KHZ' is a constant value which is also correct and doesn't case any harm. Probably will be even more expressive to write this as: target_freq = dev->avg_freq + dev->boost_freq; target_freq = tegra_actmon_account_cpu_freq(tegra, dev, target_freq); return min(target_freq, tegra->max_freq); Thank you very much for the reviews!
