@@ -158,10 +158,11 @@ static int set_freq_table(struct devfreq *devfreq)
int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
{
int lev, prev_lev, ret = 0;
unsigned long cur_time;
+ lockdep_assert_held(&devfreq->lock);
cur_time = jiffies;
/* Immediately exit if previous_freq is not initialized yet. */
if (!devfreq->previous_freq)
goto out;
@@ -1415,16 +1416,21 @@ static ssize_t trans_stat_show(struct device *dev,
struct devfreq *devfreq = to_devfreq(dev);
ssize_t len;
int i, j;
unsigned int max_state = devfreq->profile->max_state;
- if (!devfreq->stop_polling &&
- devfreq_update_status(devfreq, devfreq->previous_freq))
- return 0;
if (max_state == 0)
return sprintf(buf, "Not Supported.\n");
+ mutex_lock(&devfreq->lock);
+ if (!devfreq->stop_polling &&
+ devfreq_update_status(devfreq, devfreq->previous_freq)) {
+ mutex_unlock(&devfreq->lock);
+ return 0;
+ }
+ mutex_unlock(&devfreq->lock);
+
len = sprintf(buf, " From : To\n");
len += sprintf(buf + len, " :");
for (i = 0; i < max_state; i++)
len += sprintf(buf + len, "%10lu",
devfreq->profile->freq_table[i]);
There is no locking in this sysfs show function so stats printing can race with a devfreq_update_status called as part of freq switching or with initialization. Also add an assert in devfreq_update_status to make it clear that lock must be held by caller. Fixes: 39688ce6facd ("PM / devfreq: account suspend/resume for stats") Cc: stable@vger.kernel.org Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> --- Changes since v2: * Move assert higher * Drop useless comment * Add Fixes: tag and Cc: stable Link to v2: https://patchwork.kernel.org/patch/11157315/ Changes since v1: * Split from series: low-priority bugfix not strictly required for PM QoS * Only keep lock during update, release before sprintf Link to v1: https://patchwork.kernel.org/patch/11149493/ drivers/devfreq/devfreq.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)