Hi,
On 2016년 10월 27일 04:17, Saravana Kannan wrote:
> If the new governor fails to start, switch back to old governor so that the
> devfreq state is not left in some weird limbo.
>
> Signed-off-by: Saravana Kannan <skan...@codeaurora.org>
> ---
> * Fix NULL deref for real this time.
> * Addressed some style preferences.
>
> drivers/devfreq/devfreq.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index bf3ea76..77c41a5 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -919,7 +919,7 @@ static ssize_t governor_store(struct device *dev, struct
> device_attribute *attr,
> struct devfreq *df = to_devfreq(dev);
> int ret;
> char str_governor[DEVFREQ_NAME_LEN + 1];
> - struct devfreq_governor *governor;
> + const struct devfreq_governor *governor, *prev_governor;
>
> ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
> if (ret != 1)
> @@ -944,12 +944,21 @@ static ssize_t governor_store(struct device *dev,
> struct device_attribute *attr,
> goto out;
> }
> }
> + prev_governor = df->governor;
> df->governor = governor;
> strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
> ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
> - if (ret)
> + if (ret) {
> dev_warn(dev, "%s: Governor %s not started(%d)\n",
> __func__, df->governor->name, ret);
> + if (prev_governor) {
I think that prev_governor is always set. You don't need to check it.
Why do check it?
> + df->governor = prev_governor;
> + strncpy(df->governor_name, prev_governor->name,
> + DEVFREQ_NAME_LEN);
> + df->governor->event_handler(df, DEVFREQ_GOV_START,
> + NULL);
> + }
> + }
> out:
> mutex_unlock(&devfreq_list_lock);
>
>
--
Best Regards,
Chanwoo Choi
