diff options
| author | Leonard Crestez <leonard.crestez@nxp.com> | 2019-09-24 10:52:23 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-21 10:42:05 +0100 |
| commit | b99f20c45949968c1f40b05712d515421e18b426 (patch) | |
| tree | 69f9e461b1de098b4ef81d0a433014d846525955 /drivers/devfreq | |
| parent | 5751ba7db7d354dfdb491b9a83b24ea3d176d816 (diff) | |
PM / devfreq: Lock devfreq in trans_stat_show
commit 2abb0d5268ae7b5ddf82099b1f8d5aa8414637d4 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/devfreq')
| -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 db70cee71caa..df62e38de5f5 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -135,6 +135,7 @@ 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. */ @@ -1170,12 +1171,17 @@ 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++) |