linux-kernel - Re: [RFT PATCH] power: bq2415x_charger: Properly handle ENODEV from power_supply_get_by

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Date:	Wed, 15 Oct 2014 11:05:12 +0200
From:	Sebastian Reichel <sre@...nel.org>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [RFT PATCH] power: bq2415x_charger: Properly handle ENODEV from
 power_supply_get_by_phandle

Hi Krzysztof,

On Tue, Oct 14, 2014 at 10:32:53AM +0200, Krzysztof Kozlowski wrote:
> The power_supply_get_by_phandle() on error returns ENODEV or NULL.
> The driver later expects obtained pointer to power supply to be
> valid or NULL. If it is not NULL then it dereferences it in
> bq2415x_notifier_call() which would lead to dereferencing ENODEV-value
> pointer.
> 
> Properly handle the power_supply_get_by_phandle() error case and abort probe.
> 
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
> Fixes: faffd234cf85 ("bq2415x_charger: Add DT support")
> Cc: <stable@...r.kernel.org>

That looks valid, but I guess this should change one more thing:

> ---
>  drivers/power/bq2415x_charger.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/power/bq2415x_charger.c b/drivers/power/bq2415x_charger.c
> index e384844a1ae1..d9c457217b6a 100644
> --- a/drivers/power/bq2415x_charger.c
> +++ b/drivers/power/bq2415x_charger.c
> @@ -1579,8 +1579,13 @@ static int bq2415x_probe(struct i2c_client *client,
>  	if (np) {
>  		bq->notify_psy = power_supply_get_by_phandle(np, "ti,usb-charger-detection");
>  
> -		if (!bq->notify_psy)
> +		if (!bq->notify_psy) {
>  			return -EPROBE_DEFER;

this also needs to goto error_2. I guess something as the following
is needed:

if (IS_ERR_OR_NULL(bq->notify_psy)) {
    if (bq->notify_psy)
        dev_err(&client->dev, "no 'ti,usb-charger-detection' property\n");
    ret = PTR_ERR(bq->notify_psy);
    goto error_2;
}

> +		} else if (IS_ERR(bq->notify_psy)) {
> +			dev_err(&client->dev, "no 'ti,usb-charger-detection' property\n");
> +			ret = PTR_ERR(bq->notify_psy);
> +			goto error_2;
> +		}
>  	}
>  	else if (pdata->notify_device)
>  		bq->notify_psy = power_supply_get_by_name(pdata->notify_device);

-- Sebastian

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