Re: [PATCH] gpio: make library immune to error pointers

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On 06/16/2016 12:59 PM, Linus Walleij wrote:
Most functions that take a GPIO descriptor in need to check the
descriptor for IS_ERR(). We do this mostly in the VALIDATE_DESC()
macro except for the gpiod_to_irq() function which needs special
handling.

Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
  drivers/gpio/gpiolib.c | 6 +++---
  1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index f39bf05993e7..1a8dbc791892 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1371,7 +1371,7 @@ done:
   * optional GPIO and calls should just bail out.
   */
  #define VALIDATE_DESC(desc) do { \
-	if (!desc) \
+	if (!desc || IS_ERR(desc)) \
  		return 0; \

i do not think this right thing to return 0 here :(
if IS_ERR(desc) this is bug and drivers must handle this properly.

For example, -EPROBE_DEFER

  	if (!desc->gdev) { \
  		pr_warn("%s: invalid GPIO\n", __func__); \
@@ -1384,7 +1384,7 @@ done:
  	} } while (0)

  #define VALIDATE_DESC_VOID(desc) do { \
-	if (!desc) \
+	if (!desc || IS_ERR(desc)) \
  		return; \
  	if (!desc->gdev) { \
  		pr_warn("%s: invalid GPIO\n", __func__); \
@@ -2061,7 +2061,7 @@ int gpiod_to_irq(const struct gpio_desc *desc)
  	 * requires this function to not return zero on an invalid descriptor
  	 * but rather a negative error number.
  	 */
-	if (!desc || !desc->gdev || !desc->gdev->chip)
+	if (!desc || IS_ERR(desc) || !desc->gdev || !desc->gdev->chip)
  		return -EINVAL;

  	chip = desc->gdev->chip;



--
regards,
-grygorii
--
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