Re: [PATCH] pinctrl: madera: Fix uninitialized variable issue in madera_mux_set_mux

Charles Keepax
2018-10-10T14:34:00Z

On Wed, Oct 10, 2018 at 04:13:53PM +0200, Gustavo A. R. Silva wrote:
> There is a potential execution path in which variable *ret* is checked
> in an IF statement, and then its value is used to report an error at
> line 659 without being properly initialized previously:
>
> 659 if (ret)
> 660 dev_err(priv->dev, "Failed to write to 0x%x (%d)\n", reg, ret);
>
> Fix this by initializing variable *ret* to -1.
>
> Addresses-Coverity-ID: 1471969 ("Uninitialized scalar variable")
> Fixes: 218d72a77b0b ("pinctrl: madera: Add driver for Cirrus Logic Madera codecs")
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> drivers/pinctrl/cirrus/pinctrl-madera-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pinctrl/cirrus/pinctrl-madera-core.c b/drivers/pinctrl/cirrus/pinctrl-madera-core.c
> index 0266302..a99ace8 100644
> --- a/drivers/pinctrl/cirrus/pinctrl-madera-core.c
> +++ b/drivers/pinctrl/cirrus/pinctrl-madera-core.c
> @@ -608,7 +608,7 @@ static int madera_mux_set_mux(struct pinctrl_dev *pctldev,
> unsigned int n_chip_groups = priv->chip->n_pin_groups;
> const char *func_name = madera_mux_funcs[selector].name;
> unsigned int reg;
> - int i, ret;
> + int i, ret = -1;
>

I don't believe this would fully address the issue since if you
initialise ret to -1 you will still drop into the if statement
and you will use the reg variable which should also be
uninitialised on that code path.

Feels like initialising to 0 would probably be better anyway
since the code path looks like the case were you have n_pins == 0
and nothing really failed in that case just nothing needed to be
done.

Thanks,
Charles

> dev_dbg(priv->dev, "%s selecting %u (%s) for group %u (%s)\n",
> __func__, selector, func_name, group,
> --
> 2.7.4