| Message ID | 1393226100-18428-1-git-send-email-skannan@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/23/2014 11:15 PM, Saravana Kannan wrote: > The previous_freq value for a device could be an invalid frequency that > results in a error value being returned from devfreq_get_freq_level(). > Check for an error value before using that to index into the transition > table. > > Not doing this check will result in memory corruption when previous_freq is > not a valid frequency. > > Signed-off-by: Saravana Kannan <skannan@codeaurora.org> MyungJoo/Kyungmin, Would either of you have some time to respond to this? Thanks, Saravana
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index a0b2f7e..f91ea29 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -101,14 +101,20 @@ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) cur_time = jiffies; devfreq->time_in_state[lev] += cur_time - devfreq->last_stat_updated; - if (freq != devfreq->previous_freq) { - prev_lev = devfreq_get_freq_level(devfreq, - devfreq->previous_freq); + devfreq->last_stat_updated = cur_time; + + if (freq == devfreq->previous_freq) + return 0; + + prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); + if (prev_lev < 0) + return 0; + + 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; }
The previous_freq value for a device could be an invalid frequency that results in a error value being returned from devfreq_get_freq_level(). Check for an error value before using that to index into the transition table. Not doing this check will result in memory corruption when previous_freq is not a valid frequency. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> --- drivers/devfreq/devfreq.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)