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| author | Leonard Crestez <leonard.crestez@nxp.com> | 2019-09-24 10:52:23 +0300 |
|---|---|---|
| committer | Chanwoo Choi <cw00.choi@samsung.com> | 2019-11-06 12:04:00 +0900 |
| commit | 2abb0d5268ae7b5ddf82099b1f8d5aa8414637d4 (patch) | |
| tree | 3c6991f0a3e90ac554a58d23bcfd6cddb14928bf | |
| parent | d68adc8f85cd757bd33c8d7b2660ad6f16f7f3dc (diff) | |
| download | linux-pm-2abb0d5268ae7b5ddf82099b1f8d5aa8414637d4.tar.gz | |
PM / devfreq: Lock devfreq in trans_stat_show
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>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
| -rw-r--r-- | drivers/devfreq/devfreq.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 60859a2400bc97..d6c3dce9e9d505 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -160,6 +160,7 @@ 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. */ @@ -1397,12 +1398,17 @@ static ssize_t trans_stat_show(struct device *dev, 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++) |