[PATCH v3] tmio_mmc_pio: prevent endless loop in tmio_mmc_set_clock()

[PATCH v3] tmio_mmc_pio: prevent endless loop in tmio_mmc_set_clock()

[Sergei Shtylyov]

I spent a couple of days with the driver just hanging due to me forgetting to
specify the external crystal frequency,  so that clk_get_rate() returned 0 and
thus the loop in tmio_mmc_set_clock() never ended. I don't think that's an
acceptable behavior, so I suggest that the minimum frequency is checked for 0
in tmio_mmc_host_probe().

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: stable@vger.kernel.org

---
The patch is against Ulf Hansson's 'mmc.git' repo's 'fixes' branch.

Changes in version 3:
- added Cc: stable.

Changes in version 2:
- fixed grammar in the changelog.

 drivers/mmc/host/tmio_mmc_pio.c |    9 +++++++++
 1 file changed, 9 insertions(+)

Index: mmc/drivers/mmc/host/tmio_mmc_pio.c
===================================================================
--- mmc.orig/drivers/mmc/host/tmio_mmc_pio.c
+++ mmc/drivers/mmc/host/tmio_mmc_pio.c
@@ -1044,6 +1044,15 @@ int tmio_mmc_host_probe(struct tmio_mmc_
 	}
 
 	/*
+	 * Check the sanity of mmc->f_min to prevent tmio_mmc_set_clock() from
+	 * looping forever...
+	 */
+	if (mmc->f_min == 0) {
+		ret = -EINVAL;
+		goto pm_disable;
+	}
+
+	/*
 	 * There are 4 different scenarios for the card detection:
 	 *  1) an external gpio irq handles the cd (best for power savings)
 	 *  2) internal sdhi irq handles the cd

Re: [PATCH v3] tmio_mmc_pio: prevent endless loop in tmio_mmc_set_clock()

[Ian Molton]

Seems reasonable,

Acked-by: Ian Molton <ian.molton@codethink.co.uk>

-Ian

On Sun, 14 Sep 2014 23:51:24 +0400
Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> wrote:

> I spent a couple of days with the driver just hanging due to me forgetting to
> specify the external crystal frequency,  so that clk_get_rate() returned 0 and
> thus the loop in tmio_mmc_set_clock() never ended. I don't think that's an
> acceptable behavior, so I suggest that the minimum frequency is checked for 0
> in tmio_mmc_host_probe().
> 
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> Cc: stable@vger.kernel.org
> 
> ---
> The patch is against Ulf Hansson's 'mmc.git' repo's 'fixes' branch.
> 
> Changes in version 3:
> - added Cc: stable.
> 
> Changes in version 2:
> - fixed grammar in the changelog.
> 
>  drivers/mmc/host/tmio_mmc_pio.c |    9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> Index: mmc/drivers/mmc/host/tmio_mmc_pio.c
> ===================================================================
> --- mmc.orig/drivers/mmc/host/tmio_mmc_pio.c
> +++ mmc/drivers/mmc/host/tmio_mmc_pio.c
> @@ -1044,6 +1044,15 @@ int tmio_mmc_host_probe(struct tmio_mmc_
>  	}
>  
>  	/*
> +	 * Check the sanity of mmc->f_min to prevent tmio_mmc_set_clock() from
> +	 * looping forever...
> +	 */
> +	if (mmc->f_min == 0) {
> +		ret = -EINVAL;
> +		goto pm_disable;
> +	}
> +
> +	/*
>  	 * There are 4 different scenarios for the card detection:
>  	 *  1) an external gpio irq handles the cd (best for power savings)
>  	 *  2) internal sdhi irq handles the cd
> 


-- 
Ian Molton <ian.molton@codethink.co.uk>

Re: [PATCH v3] tmio_mmc_pio: prevent endless loop in tmio_mmc_set_clock()

[Ulf Hansson]

On 14 September 2014 21:51, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
> I spent a couple of days with the driver just hanging due to me forgetting to
> specify the external crystal frequency,  so that clk_get_rate() returned 0 and
> thus the loop in tmio_mmc_set_clock() never ended. I don't think that's an
> acceptable behavior, so I suggest that the minimum frequency is checked for 0
> in tmio_mmc_host_probe().
>
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> Cc: stable@vger.kernel.org
>
> ---
> The patch is against Ulf Hansson's 'mmc.git' repo's 'fixes' branch.

Hi Sergei,

Could you please rebase it towards next instead?

Kind regards
Uffe

>
> Changes in version 3:
> - added Cc: stable.
>
> Changes in version 2:
> - fixed grammar in the changelog.
>
>  drivers/mmc/host/tmio_mmc_pio.c |    9 +++++++++
>  1 file changed, 9 insertions(+)
>
> Index: mmc/drivers/mmc/host/tmio_mmc_pio.c
> ===================================================================
> --- mmc.orig/drivers/mmc/host/tmio_mmc_pio.c
> +++ mmc/drivers/mmc/host/tmio_mmc_pio.c
> @@ -1044,6 +1044,15 @@ int tmio_mmc_host_probe(struct tmio_mmc_
>         }
>
>         /*
> +        * Check the sanity of mmc->f_min to prevent tmio_mmc_set_clock() from
> +        * looping forever...
> +        */
> +       if (mmc->f_min == 0) {
> +               ret = -EINVAL;
> +               goto pm_disable;
> +       }
> +
> +       /*
>          * There are 4 different scenarios for the card detection:
>          *  1) an external gpio irq handles the cd (best for power savings)
>          *  2) internal sdhi irq handles the cd
>

Re: [PATCH v3] tmio_mmc_pio: prevent endless loop in tmio_mmc_set_clock()

[Sergei Shtylyov]

Hello.

On 9/18/2014 1:03 AM, Ulf Hansson wrote:

>> I spent a couple of days with the driver just hanging due to me forgetting to
>> specify the external crystal frequency,  so that clk_get_rate() returned 0 and
>> thus the loop in tmio_mmc_set_clock() never ended. I don't think that's an
>> acceptable behavior, so I suggest that the minimum frequency is checked for 0
>> in tmio_mmc_host_probe().

>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
>> Cc: stable@vger.kernel.org

>> ---
>> The patch is against Ulf Hansson's 'mmc.git' repo's 'fixes' branch.

> Hi Sergei,

> Could you please rebase it towards next instead?

    Ah, I've misinterpreted your mail, thought that I should either rebase to 
next /or/ CC: stable. Will do.

> Kind regards
> Uffe

WBR, Sergei