Re: [PATCH RESEND] pinctrl: single: fix potential NULL dereference in pcs_get_function()

On Wed, 21 Aug 2024 14:21:32 +0800 Ma Ke make24@iscas.ac.cn wrote:

pinmux_generic_get_function() can return NULL and the pointer 'function' was dereferenced without checking against NULL. Add checking of pointer 'function' in pcs_get_function().

Found by code review.

...

--- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -345,6 +345,8 @@ static int pcs_get_function(struct pinctrl_dev *pctldev, unsigned pin, return -ENOTSUPP; fselector = setting->func; function = pinmux_generic_get_function(pctldev, fselector);

• if (!function)

• return -EINVAL;
  

  *func = function->data; if (!(*func)) { dev_err(pcs->dev, "%s could not find function%i\n",

Maybe. Or maybe pinmux_generic_get_function() must always return a valid pointer, in which case

BUG_ON(!function);

is an appropriate thing. But a null-pointer deref gives us the same info, so no change is needed.

btw, pinmux_generic_get_function() is funny:

if (!function) return NULL;

return function;