[PATCH] can: mpc5xxx_can: check of_iomap return before use

[PATCH] can: mpc5xxx_can: check of_iomap return before use

[Nicholas Mc Guire]

 of_iompa() can return NULL so that return needs to be checked and NULL
treated as failure. While at it also take care of the missing
of_node_put() in the error path.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Fixes: commit afa17a500a36 ("net/can: add driver for mscan family & mpc52xx_mscan")
---

Problem was found by an experimental coccinelle script

Patch was compiletested with: mpc5200_defconfig + CONFIG_CAN=y,
CONFIG_CAN_MSCAN=y, CONFIG_CAN_MPC5XXX=y
(with a number of sparse warnings not related to the proposed change)

Patch is against 4.18-rc3 (localversion-next is next-20180706)

 drivers/net/can/mscan/mpc5xxx_can.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
index c7427bd..2949a38 100644
--- a/drivers/net/can/mscan/mpc5xxx_can.c
+++ b/drivers/net/can/mscan/mpc5xxx_can.c
@@ -86,6 +86,11 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
 		return 0;
 	}
 	cdm = of_iomap(np_cdm, 0);
+	if (!cdm) {
+		of_node_put(np_cdm);
+		dev_err(&ofdev->dev, "can't map clock node!\n");
+		return 0;
+	}
 
 	if (in_8(&cdm->ipb_clk_sel) & 0x1)
 		freq *= 2;
-- 
2.1.4

Re: [PATCH] can: mpc5xxx_can: check of_iomap return before use

[Fabio Estevam]

On Mon, Jul 9, 2018 at 4:16 PM, Nicholas Mc Guire <hofrat@osadl.org> wrote:
>  of_iompa() can return NULL so that return needs to be checked and NULL

s/of_iompa/of_iomap/

> treated as failure. While at it also take care of the missing
> of_node_put() in the error path.
>
> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
> Fixes: commit afa17a500a36 ("net/can: add driver for mscan family & mpc52xx_mscan")
> ---
>
> Problem was found by an experimental coccinelle script
>
> Patch was compiletested with: mpc5200_defconfig + CONFIG_CAN=y,
> CONFIG_CAN_MSCAN=y, CONFIG_CAN_MPC5XXX=y
> (with a number of sparse warnings not related to the proposed change)
>
> Patch is against 4.18-rc3 (localversion-next is next-20180706)
>
>  drivers/net/can/mscan/mpc5xxx_can.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
> index c7427bd..2949a38 100644
> --- a/drivers/net/can/mscan/mpc5xxx_can.c
> +++ b/drivers/net/can/mscan/mpc5xxx_can.c
> @@ -86,6 +86,11 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
>                 return 0;
>         }
>         cdm = of_iomap(np_cdm, 0);
> +       if (!cdm) {
> +               of_node_put(np_cdm);
> +               dev_err(&ofdev->dev, "can't map clock node!\n");
> +               return 0;

I think you should return an error code here. -ENOMEM maybe?

Re: [PATCH] can: mpc5xxx_can: check of_iomap return before use

[Nicholas Mc Guire]

On Mon, Jul 09, 2018 at 04:28:41PM -0300, Fabio Estevam wrote:
> On Mon, Jul 9, 2018 at 4:16 PM, Nicholas Mc Guire <hofrat@osadl.org> wrote:
> >  of_iompa() can return NULL so that return needs to be checked and NULL
> 
> s/of_iompa/of_iomap/

sorry -  thats a stupid one.

> 
> > treated as failure. While at it also take care of the missing
> > of_node_put() in the error path.
> >
> > Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
> > Fixes: commit afa17a500a36 ("net/can: add driver for mscan family & mpc52xx_mscan")
> > ---
> >
> > Problem was found by an experimental coccinelle script
> >
> > Patch was compiletested with: mpc5200_defconfig + CONFIG_CAN=y,
> > CONFIG_CAN_MSCAN=y, CONFIG_CAN_MPC5XXX=y
> > (with a number of sparse warnings not related to the proposed change)
> >
> > Patch is against 4.18-rc3 (localversion-next is next-20180706)
> >
> >  drivers/net/can/mscan/mpc5xxx_can.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
> > index c7427bd..2949a38 100644
> > --- a/drivers/net/can/mscan/mpc5xxx_can.c
> > +++ b/drivers/net/can/mscan/mpc5xxx_can.c
> > @@ -86,6 +86,11 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
> >                 return 0;
> >         }
> >         cdm = of_iomap(np_cdm, 0);
> > +       if (!cdm) {
> > +               of_node_put(np_cdm);
> > +               dev_err(&ofdev->dev, "can't map clock node!\n");
> > +               return 0;
> 
> I think you should return an error code here. -ENOMEM maybe?

I don´t think so the code above this part return 0 on error and a
valid frequency on success so returning -ENOMEM would probably be
mistaken as a frequency !

thx!
hofrat

Re: [PATCH] can: mpc5xxx_can: check of_iomap return before use

[Fabio Estevam]

On Mon, Jul 9, 2018 at 4:31 PM, Nicholas Mc Guire <der.herr@hofr.at> wrote:

> I don´t think so the code above this part return 0 on error and a
> valid frequency on success so returning -ENOMEM would probably be
> mistaken as a frequency !

Now that I looked closely in the function context I see it makes sense
to return 0 :-)

Thanks

Re: [PATCH] can: mpc5xxx_can: check of_iomap return before use

[Marc Kleine-Budde]

[-- Attachment #1.1: Type: text/plain, Size: 1853 bytes --]

On 07/09/2018 09:28 PM, Fabio Estevam wrote:
> On Mon, Jul 9, 2018 at 4:16 PM, Nicholas Mc Guire <hofrat@osadl.org> wrote:
>>  of_iompa() can return NULL so that return needs to be checked and NULL
> 
> s/of_iompa/of_iomap/
> 
>> treated as failure. While at it also take care of the missing
>> of_node_put() in the error path.
>>
>> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
>> Fixes: commit afa17a500a36 ("net/can: add driver for mscan family & mpc52xx_mscan")
>> ---
>>
>> Problem was found by an experimental coccinelle script
>>
>> Patch was compiletested with: mpc5200_defconfig + CONFIG_CAN=y,
>> CONFIG_CAN_MSCAN=y, CONFIG_CAN_MPC5XXX=y
>> (with a number of sparse warnings not related to the proposed change)
>>
>> Patch is against 4.18-rc3 (localversion-next is next-20180706)
>>
>>  drivers/net/can/mscan/mpc5xxx_can.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
>> index c7427bd..2949a38 100644
>> --- a/drivers/net/can/mscan/mpc5xxx_can.c
>> +++ b/drivers/net/can/mscan/mpc5xxx_can.c
>> @@ -86,6 +86,11 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
>>                 return 0;
>>         }
>>         cdm = of_iomap(np_cdm, 0);
>> +       if (!cdm) {
>> +               of_node_put(np_cdm);
>> +               dev_err(&ofdev->dev, "can't map clock node!\n");
>> +               return 0;
> 
> I think you should return an error code here. -ENOMEM maybe?

Can you send an updated version?

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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Re: [PATCH] can: mpc5xxx_can: check of_iomap return before use

[Nicholas Mc Guire]

On Mon, Jul 23, 2018 at 01:37:05PM +0200, Marc Kleine-Budde wrote:
> On 07/09/2018 09:28 PM, Fabio Estevam wrote:
> > On Mon, Jul 9, 2018 at 4:16 PM, Nicholas Mc Guire <hofrat@osadl.org> wrote:
> >>  of_iompa() can return NULL so that return needs to be checked and NULL
> > 
> > s/of_iompa/of_iomap/
> > 
> >> treated as failure. While at it also take care of the missing
> >> of_node_put() in the error path.
> >>
> >> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
> >> Fixes: commit afa17a500a36 ("net/can: add driver for mscan family & mpc52xx_mscan")
> >> ---
> >>
> >> Problem was found by an experimental coccinelle script
> >>
> >> Patch was compiletested with: mpc5200_defconfig + CONFIG_CAN=y,
> >> CONFIG_CAN_MSCAN=y, CONFIG_CAN_MPC5XXX=y
> >> (with a number of sparse warnings not related to the proposed change)
> >>
> >> Patch is against 4.18-rc3 (localversion-next is next-20180706)
> >>
> >>  drivers/net/can/mscan/mpc5xxx_can.c | 5 +++++
> >>  1 file changed, 5 insertions(+)
> >>
> >> diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
> >> index c7427bd..2949a38 100644
> >> --- a/drivers/net/can/mscan/mpc5xxx_can.c
> >> +++ b/drivers/net/can/mscan/mpc5xxx_can.c
> >> @@ -86,6 +86,11 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
> >>                 return 0;
> >>         }
> >>         cdm = of_iomap(np_cdm, 0);
> >> +       if (!cdm) {
> >> +               of_node_put(np_cdm);
> >> +               dev_err(&ofdev->dev, "can't map clock node!\n");
> >> +               return 0;
> > 
> > I think you should return an error code here. -ENOMEM maybe?
> 
> Can you send an updated version?
>
The way I understand the code the return value will be used
as a frequency - the only valid error valeu thus is 0 here,
so I think the return 0 is correct.

thx!
hofrat

Re: [PATCH] can: mpc5xxx_can: check of_iomap return before use

[Marc Kleine-Budde]

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On 07/23/2018 01:57 PM, Nicholas Mc Guire wrote:
> On Mon, Jul 23, 2018 at 01:37:05PM +0200, Marc Kleine-Budde wrote:
>> On 07/09/2018 09:28 PM, Fabio Estevam wrote:
>>> On Mon, Jul 9, 2018 at 4:16 PM, Nicholas Mc Guire <hofrat@osadl.org> wrote:
>>>>  of_iompa() can return NULL so that return needs to be checked and NULL
>>>
>>> s/of_iompa/of_iomap/
>>>
>>>> treated as failure. While at it also take care of the missing
>>>> of_node_put() in the error path.
>>>>
>>>> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
>>>> Fixes: commit afa17a500a36 ("net/can: add driver for mscan family & mpc52xx_mscan")
>>>> ---
>>>>
>>>> Problem was found by an experimental coccinelle script
>>>>
>>>> Patch was compiletested with: mpc5200_defconfig + CONFIG_CAN=y,
>>>> CONFIG_CAN_MSCAN=y, CONFIG_CAN_MPC5XXX=y
>>>> (with a number of sparse warnings not related to the proposed change)
>>>>
>>>> Patch is against 4.18-rc3 (localversion-next is next-20180706)
>>>>
>>>>  drivers/net/can/mscan/mpc5xxx_can.c | 5 +++++
>>>>  1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/drivers/net/can/mscan/mpc5xxx_can.c b/drivers/net/can/mscan/mpc5xxx_can.c
>>>> index c7427bd..2949a38 100644
>>>> --- a/drivers/net/can/mscan/mpc5xxx_can.c
>>>> +++ b/drivers/net/can/mscan/mpc5xxx_can.c
>>>> @@ -86,6 +86,11 @@ static u32 mpc52xx_can_get_clock(struct platform_device *ofdev,
>>>>                 return 0;
>>>>         }
>>>>         cdm = of_iomap(np_cdm, 0);
>>>> +       if (!cdm) {
>>>> +               of_node_put(np_cdm);
>>>> +               dev_err(&ofdev->dev, "can't map clock node!\n");
>>>> +               return 0;
>>>
>>> I think you should return an error code here. -ENOMEM maybe?
>>
>> Can you send an updated version?
>>
> The way I understand the code the return value will be used
> as a frequency - the only valid error valeu thus is 0 here,
> so I think the return 0 is correct.

Yes. Looking at the code this makes sense.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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