From: Damien Le Moal <damien.lemoal@wdc.com>
To: Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
linux-gpio@vger.kernel.org
Subject: [PATCH] gpio: Do not trigger WARN() with sysfs gpio export/unexport
Date: Wed, 4 Nov 2020 20:53:48 +0900 [thread overview]
Message-ID: <20201104115348.51930-1-damien.lemoal@wdc.com> (raw)
If a user tries to export or unexport an invalid gpio (e.g. gpio number
>= ARCH_NR_GPIOS), gpio_to_desc() will trigger a register dump through a
WARN() call. Avoid this rather scary error message by first checking the
validity of the gpio number before calling gpio_to_desc() in
export_store() and unexport_store(). The user gets a normal error
message to signal his/her error without any possible confusion with a
kernel bug.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
drivers/gpio/gpiolib-sysfs.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 728f6c687182..b6fd0d82757a 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -3,6 +3,7 @@
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/sysfs.h>
+#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
@@ -456,14 +457,15 @@ static ssize_t export_store(struct class *class,
const char *buf, size_t len)
{
long gpio;
- struct gpio_desc *desc;
+ struct gpio_desc *desc = NULL;
int status;
status = kstrtol(buf, 0, &gpio);
if (status < 0)
goto done;
- desc = gpio_to_desc(gpio);
+ if (gpio_is_valid(gpio))
+ desc = gpio_to_desc(gpio);
/* reject invalid GPIOs */
if (!desc) {
pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
@@ -503,14 +505,15 @@ static ssize_t unexport_store(struct class *class,
const char *buf, size_t len)
{
long gpio;
- struct gpio_desc *desc;
+ struct gpio_desc *desc = NULL;
int status;
status = kstrtol(buf, 0, &gpio);
if (status < 0)
goto done;
- desc = gpio_to_desc(gpio);
+ if (gpio_is_valid(gpio))
+ desc = gpio_to_desc(gpio);
/* reject bogus commands (gpio_unexport ignores them) */
if (!desc) {
pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
--
2.28.0
next reply other threads:[~2020-11-04 11:55 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 11:53 Damien Le Moal [this message]
2020-11-06 9:27 ` [PATCH] gpio: Do not trigger WARN() with sysfs gpio export/unexport Bartosz Golaszewski
2020-11-06 11:27 ` Damien Le Moal
2020-11-10 14:31 ` Linus Walleij
2020-11-10 14:40 ` Bartosz Golaszewski
2020-11-10 15:09 ` Michael Walle
2020-11-11 7:14 ` Damien Le Moal
2020-11-11 7:20 ` Damien Le Moal
2020-11-11 7:11 ` Damien Le Moal
2020-11-11 6:54 ` Damien Le Moal
2020-11-11 15:14 ` Linus Walleij
2020-11-19 18:50 ` Geert Uytterhoeven
2020-11-10 14:22 ` Linus Walleij
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