From 533acc0e8df7d6553f11cf91c177211cb6037968 Mon Sep 17 00:00:00 2001 From: Xiubo Li Date: Mon, 18 Aug 2014 17:08:44 +0800 Subject: pwm: Fix possible ZERO_SIZE_PTR pointer dereferencing error. Since we cannot make sure the 'chip->npwm' will always be none zero here, and then if either equal to zero, the kzalloc() will return ZERO_SIZE_PTR, which equals to ((void *)16). So this patch fix this with just doing the zero check before calling kzalloc(). Signed-off-by: Xiubo Li Signed-off-by: Thierry Reding --- drivers/pwm/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pwm/core.c') diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index d2c35920ff08..8c748b17f416 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -236,7 +236,7 @@ int pwmchip_add(struct pwm_chip *chip) int ret; if (!chip || !chip->dev || !chip->ops || !chip->ops->config || - !chip->ops->enable || !chip->ops->disable) + !chip->ops->enable || !chip->ops->disable || !chip->npwm) return -EINVAL; mutex_lock(&pwm_lock); -- cgit v1.2.3 From 70145f87139fbc43b726f873813cd91dce371899 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 28 Aug 2014 11:03:14 +0200 Subject: pwm: Fix uninitialized warnings in pwm_get() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With some versions of gcc (e.g. 4.1.2): drivers/pwm/core.c: In function ‘pwm_get’: drivers/pwm/core.c:610: warning: ‘polarity’ may be used uninitialized in this function drivers/pwm/core.c:609: warning: ‘period’ may be used uninitialized in this function While these are false positives, we can get rid of them by refactoring the code to store a pointer to the best match, as suggested before by Thierry Reding. This does require moving the mutex_unlock() down. Fixes: d717ea73e36dd565 ("pwm: Fix period and polarity in pwm_get() for non-perfect matches") Signed-off-by: Geert Uytterhoeven Signed-off-by: Thierry Reding --- drivers/pwm/core.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) (limited to 'drivers/pwm/core.c') diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 8c748b17f416..966497d10c6e 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -602,12 +602,9 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER); const char *dev_id = dev ? dev_name(dev) : NULL; struct pwm_chip *chip = NULL; - unsigned int index = 0; unsigned int best = 0; - struct pwm_lookup *p; + struct pwm_lookup *p, *chosen = NULL; unsigned int match; - unsigned int period; - enum pwm_polarity polarity; /* look up via DT first */ if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) @@ -653,10 +650,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) } if (match > best) { - chip = pwmchip_find_by_name(p->provider); - index = p->index; - period = p->period; - polarity = p->polarity; + chosen = p; if (match != 3) best = match; @@ -665,17 +659,22 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) } } - mutex_unlock(&pwm_lookup_lock); + if (!chosen) + goto out; - if (chip) - pwm = pwm_request_from_chip(chip, index, con_id ?: dev_id); - if (IS_ERR(pwm)) - return pwm; + chip = pwmchip_find_by_name(chosen->provider); + if (!chip) + goto out; - pwm_set_period(pwm, period); - pwm_set_polarity(pwm, polarity); + pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id); + if (IS_ERR(pwm)) + goto out; + pwm_set_period(pwm, chosen->period); + pwm_set_polarity(pwm, chosen->polarity); +out: + mutex_unlock(&pwm_lookup_lock); return pwm; } EXPORT_SYMBOL_GPL(pwm_get); -- cgit v1.2.3