linux-kernel - Re: [PATCH] mfd: max77843: Fix max77843_chg

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Date:	Sun, 20 Sep 2015 05:17:39 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	Javier Martinez Canillas <javier@....samsung.com>,
	linux-kernel@...r.kernel.org, Samuel Ortiz <sameo@...ux.intel.com>
Subject: Re: [PATCH] mfd: max77843: Fix max77843_chg_init() return on error

On Tue, 15 Sep 2015, Krzysztof Kozlowski wrote:

> 2015-09-14 17:23 GMT+09:00 Javier Martinez Canillas <javier@....samsung.com>:
> > If i2c_new_dummy() fails in max77843_chg_init(), an PTR_ERR(NULL) is
> > returned which is 0. So the function was wrongly returning a success
> > value instead of an error code.
> >
> > Fixes: c7f585fe46d8 ("mfd: max77843: Add max77843 MFD driver core driver")
> > Signed-off-by: Javier Martinez Canillas <javier@....samsung.com>
> >
> > ---
> >
> >  drivers/mfd/max77843.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Nice catch. I think this should go to stable. I did not try to
> reproduce it but looking at the code this should lead to NULL pointer
> exceptions on:
> 1. first access to max77843->regmap_chg (this won't actually happen
> because charger driver was not merged);
> 2. first dereference of pointer returned by i2c_get_clientdata() which
> will happen on first system suspend or device unbind/removal.
> 
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>

Please re-send this with stable Cc'ed and Krzysztof's RB applied.

> > diff --git a/drivers/mfd/max77843.c b/drivers/mfd/max77843.c
> > index c52162ea3d0a..586098f1b233 100644
> > --- a/drivers/mfd/max77843.c
> > +++ b/drivers/mfd/max77843.c
> > @@ -80,7 +80,7 @@ static int max77843_chg_init(struct max77693_dev *max77843)
> >         if (!max77843->i2c_chg) {
> >                 dev_err(&max77843->i2c->dev,
> >                                 "Cannot allocate I2C device for Charger\n");
> > -               return PTR_ERR(max77843->i2c_chg);
> > +               return -ENODEV;
> >         }
> >         i2c_set_clientdata(max77843->i2c_chg, max77843);
> >
> >

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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