When selecting the idle state using cpuidle_select, there is no check on cpuidle_curr_governor. In cpuidle_switch_governor, cpuidle_currr_governor can be set to NULL to specify "disabled".
Since cpuidle_select cannot return negative value, it has to return 0 in case of error. Printing logs and returning can help in debugging and preventing possible kernel crash scenarios. Signed-off-by: Gaurav Jindal<[email protected]> --- diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 68a1682..bf08e3a 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -268,6 +268,19 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, */ int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) { + + /* Since negative return is not allowed + * we have to return 0 even if the + * framework cannot select the idle state + */ + if (!cpuidle_curr_governor) { + pr_err("idle governor is disabled\n"); + return 0; + } + if (!cpuidle_curr_governor->select) { + pr_err("idle governor select is NULL\n"); + return 0; + } return cpuidle_curr_governor->select(drv, dev); }
