@@ -115,7 +115,14 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
}
if (pwm->chip->ops->get_state) {
- struct pwm_state state;
+ /*
+ * Zero-initialize state because most drivers are unaware of
+ * .usage_power. The other members of state are supposed to be
+ * set by lowlevel drivers. We still initialize the whole
+ * structure for simplicity even though this might paper over
+ * faulty implementations of .get_state().
+ */
+ struct pwm_state state = { 0, };
err = pwm->chip->ops->get_state(pwm->chip, pwm, &state);
trace_pwm_get(pwm, &state, err);
@@ -448,7 +455,7 @@ static void pwm_apply_state_debug(struct pwm_device *pwm,
{
struct pwm_state *last = &pwm->last;
struct pwm_chip *chip = pwm->chip;
- struct pwm_state s1, s2;
+ struct pwm_state s1 = { 0 }, s2 = { 0 };
int err;
if (!IS_ENABLED(CONFIG_PWM_DEBUG))
@@ -530,6 +537,7 @@ static void pwm_apply_state_debug(struct pwm_device *pwm,
return;
}
+ *last = (struct pwm_state){ 0 };
err = chip->ops->get_state(chip, pwm, last);
trace_pwm_get(pwm, last, err);
if (err)
This is just to ensure that .usage_power is properly initialized and doesn't contain random stack data. The other members of struct pwm_state should get a value assigned in a successful call to .get_state(). So in the absence of bugs in driver implementations, this is only a safe-guard and no fix. Reported-by: Munehisa Kamata <kamatam@amazon.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- Hello, I found a few more locations where .get_state() is called without zero-initializing *state. Best regards Uwe drivers/pwm/core.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) base-commit: cf70d01a62c712ee715df1f7892b58c77474bcfb