| Message ID | 1393558737-24037-1-git-send-email-skannan@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/27/2014 07:38 PM, Saravana Kannan wrote: > The current devfreq_update_status() has the following bugs: > - If previous frequency doesn't have a valid level, it does an out of bounds > access into the trans_table and causes memory corruption. > - When the new frequency doesn't have a valid level, the time spent in the > new frequency is counted towards the next valid frequency switch instead of > being ignored. > - The time spent on the previous frequency is added to the new frequency's > stats instead of the previous frequency's stats. > > This patch fixes all of this. > > Signed-off-by: Saravana Kannan <skannan@codeaurora.org> > --- MyungJoo/Kyungmin, Can you please take a look and let me know if this looks ok? Any possibility of getting this into 3.14? Thanks, Saravana
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index a0b2f7e..2042ec3 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -91,26 +91,35 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq) */ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) { - int lev, prev_lev; + int lev, prev_lev, ret = 0; unsigned long cur_time; - lev = devfreq_get_freq_level(devfreq, freq); - if (lev < 0) - return lev; - cur_time = jiffies; - devfreq->time_in_state[lev] += + + prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); + if (prev_lev < 0) { + ret = prev_lev; + goto out; + } + + devfreq->time_in_state[prev_lev] += cur_time - devfreq->last_stat_updated; - if (freq != devfreq->previous_freq) { - prev_lev = devfreq_get_freq_level(devfreq, - devfreq->previous_freq); + + lev = devfreq_get_freq_level(devfreq, freq); + if (lev < 0) { + ret = lev; + goto out; + } + + if (lev != prev_lev) { devfreq->trans_table[(prev_lev * devfreq->profile->max_state) + lev]++; devfreq->total_trans++; } - devfreq->last_stat_updated = cur_time; - return 0; +out: + devfreq->last_stat_updated = cur_time; + return ret; } /**
The current devfreq_update_status() has the following bugs: - If previous frequency doesn't have a valid level, it does an out of bounds access into the trans_table and causes memory corruption. - When the new frequency doesn't have a valid level, the time spent in the new frequency is counted towards the next valid frequency switch instead of being ignored. - The time spent on the previous frequency is added to the new frequency's stats instead of the previous frequency's stats. This patch fixes all of this. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> --- drivers/devfreq/devfreq.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-)