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authorSaravana Kannan <skannan@codeaurora.org>2014-02-28 03:38:57 (GMT)
committerJonghwa Lee <jonghwa3.lee@samsung.com>2014-05-15 09:59:12 (GMT)
commitb628c27e82564ebde786838702343638feb70600 (patch)
treefbb1a3aa369e93032f66b2ae5a02abe0116aeb4d
parent42da8cb46f0664455f7ac4361bc138d707f520f7 (diff)
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PM / devfreq: Rewrite devfreq_update_status() to fix multiple bugs
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. Change-Id: I9e3bb6ac6490d8f2e4bca2fd0d082f2fbd4a5b2e Signed-off-by: Saravana Kannan <skannan@codeaurora.org> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
-rw-r--r--drivers/devfreq/devfreq.c31
1 files changed, 20 insertions, 11 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 250b22d..1e4c717 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;
}
/**