[PATCH] clk: qcom: Fix a possible NULL pointer dereferencing

[PATCH] clk: qcom: Fix a possible NULL pointer dereferencing

[Vivek Gautam]

Assign num_parents as 0 while registering fixed rate clocks
in _qcom_cc_register_board_clk(), to make sure the clk framework
doesn't dereference parent.

Fixes: ee15faffef11 ("clk: qcom: common: Add API to register board clocks backwards compatibly")

Cc: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
---

Based on 'clk-next'. Build tested.

 drivers/clk/qcom/common.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
index cfab7b400381..df004ead1bef 100644
--- a/drivers/clk/qcom/common.c
+++ b/drivers/clk/qcom/common.c
@@ -157,6 +157,7 @@ static int _qcom_cc_register_board_clk(struct device *dev, const char *path,
 
 		init_data.name = path;
 		init_data.ops = &clk_fixed_rate_ops;
+		init_data.num_parents = 0;
 
 		ret = devm_clk_hw_register(dev, &fixed->hw);
 		if (ret)
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH] clk: qcom: Fix a possible NULL pointer dereferencing

[Andy Gross]

On Thu, Jan 05, 2017 at 02:25:25PM +0530, Vivek Gautam wrote:
> Assign num_parents as 0 while registering fixed rate clocks
> in _qcom_cc_register_board_clk(), to make sure the clk framework
> doesn't dereference parent.
> 
> Fixes: ee15faffef11 ("clk: qcom: common: Add API to register board clocks backwards compatibly")
> 
> Cc: Georgi Djakov <georgi.djakov@linaro.org>
> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> ---
> 
> Based on 'clk-next'. Build tested.
> 
>  drivers/clk/qcom/common.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
> index cfab7b400381..df004ead1bef 100644
> --- a/drivers/clk/qcom/common.c
> +++ b/drivers/clk/qcom/common.c
> @@ -157,6 +157,7 @@ static int _qcom_cc_register_board_clk(struct device *dev, const char *path,
>  
>  		init_data.name = path;
>  		init_data.ops = &clk_fixed_rate_ops;
> +		init_data.num_parents = 0;

It seems like there was a initializer in the declaration but it was { } instead
of { 0 }.

Was the original intent to make this structure initialized to 0?  If so, perhaps
it should be fixed above in the initializer.

>  
>  		ret = devm_clk_hw_register(dev, &fixed->hw);
>  		if (ret)


Regards,

Andy

Re: [PATCH] clk: qcom: Fix a possible NULL pointer dereferencing

[Vivek Gautam]

On 01/05/2017 07:50 PM, Andy Gross wrote:
> On Thu, Jan 05, 2017 at 02:25:25PM +0530, Vivek Gautam wrote:
>> Assign num_parents as 0 while registering fixed rate clocks
>> in _qcom_cc_register_board_clk(), to make sure the clk framework
>> doesn't dereference parent.
>>
>> Fixes: ee15faffef11 ("clk: qcom: common: Add API to register board clocks backwards compatibly")
>>
>> Cc: Georgi Djakov<georgi.djakov@linaro.org>
>> Signed-off-by: Vivek Gautam<vivek.gautam@codeaurora.org>
>> ---
>>
>> Based on 'clk-next'. Build tested.
>>
>>   drivers/clk/qcom/common.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
>> index cfab7b400381..df004ead1bef 100644
>> --- a/drivers/clk/qcom/common.c
>> +++ b/drivers/clk/qcom/common.c
>> @@ -157,6 +157,7 @@ static int _qcom_cc_register_board_clk(struct device *dev, const char *path,
>>   
>>   		init_data.name = path;
>>   		init_data.ops = &clk_fixed_rate_ops;
>> +		init_data.num_parents = 0;
> It seems like there was a initializer in the declaration but it was { } instead
> of { 0 }.
>
> Was the original intent to make this structure initialized to 0?  If so, perhaps
> it should be fixed above in the initializer.

yes, i think we intend to initialize the clock init data to 0, and thus
we should do that during declaration.
Will modify and re-spin the patch.


Regards
Vivek

>>   
>>   		ret = devm_clk_hw_register(dev, &fixed->hw);
>>   		if (ret)
> Regards,
>
> Andy
> --
> To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
> the body of a message tomajordomo@vger.kernel.org
> More majordomo info athttp://vger.kernel.org/majordomo-info.html

-- 
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH] clk: qcom: Fix a possible NULL pointer dereferencing

[Stephen Boyd]

On 01/05, Vivek Gautam wrote:
> 
> On 01/05/2017 07:50 PM, Andy Gross wrote:
> >On Thu, Jan 05, 2017 at 02:25:25PM +0530, Vivek Gautam wrote:
> >>Assign num_parents as 0 while registering fixed rate clocks
> >>in _qcom_cc_register_board_clk(), to make sure the clk framework
> >>doesn't dereference parent.
> >>
> >>Fixes: ee15faffef11 ("clk: qcom: common: Add API to register board clocks backwards compatibly")
> >>
> >>Cc: Georgi Djakov<georgi.djakov@linaro.org>
> >>Signed-off-by: Vivek Gautam<vivek.gautam@codeaurora.org>
> >>---
> >>
> >>Based on 'clk-next'. Build tested.
> >>
> >>  drivers/clk/qcom/common.c | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >>diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
> >>index cfab7b400381..df004ead1bef 100644
> >>--- a/drivers/clk/qcom/common.c
> >>+++ b/drivers/clk/qcom/common.c
> >>@@ -157,6 +157,7 @@ static int _qcom_cc_register_board_clk(struct device *dev, const char *path,
> >>  		init_data.name = path;
> >>  		init_data.ops = &clk_fixed_rate_ops;
> >>+		init_data.num_parents = 0;
> >It seems like there was a initializer in the declaration but it was { } instead
> >of { 0 }.
> >
> >Was the original intent to make this structure initialized to 0?  If so, perhaps
> >it should be fixed above in the initializer.
> 
> yes, i think we intend to initialize the clock init data to 0, and thus
> we should do that during declaration.
> Will modify and re-spin the patch.
> 

What's the error exactly? Do you have some call stack/crash that
could be put in the commit text?

It was my understanding that GCC allows braces without anything
inside to initialize structures to 0, so I'm confused what's
wrong here. If this is actually a problem then we have other
places to fix this.

 $ git grep "clk_init_data.*{ *}"
 drivers/clk/bcm/clk-bcm53573-ilp.c:     struct clk_init_data init = { };
 drivers/clk/clk-gpio.c: struct clk_init_data init = {};
 drivers/clk/clk-qoriq.c:        struct clk_init_data init = {};
 drivers/clk/clk-rk808.c:        struct clk_init_data init = {};
 drivers/clk/mediatek/clk-apmixed.c:     struct clk_init_data init = {};
 drivers/clk/mediatek/clk-gate.c:        struct clk_init_data init = {};
 drivers/clk/mediatek/clk-pll.c: struct clk_init_data init = {};
 drivers/clk/qcom/common.c:      struct clk_init_data init_data = { };
 drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c:        struct clk_init_data bytediv_init = { };

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH] clk: qcom: Fix a possible NULL pointer dereferencing

[Vivek Gautam]

Hi,

On 01/06/2017 04:09 AM, Stephen Boyd wrote:
> On 01/05, Vivek Gautam wrote:
>> On 01/05/2017 07:50 PM, Andy Gross wrote:
>>> On Thu, Jan 05, 2017 at 02:25:25PM +0530, Vivek Gautam wrote:
>>>> Assign num_parents as 0 while registering fixed rate clocks
>>>> in _qcom_cc_register_board_clk(), to make sure the clk framework
>>>> doesn't dereference parent.
>>>>
>>>> Fixes: ee15faffef11 ("clk: qcom: common: Add API to register board clocks backwards compatibly")
>>>>
>>>> Cc: Georgi Djakov<georgi.djakov@linaro.org>
>>>> Signed-off-by: Vivek Gautam<vivek.gautam@codeaurora.org>
>>>> ---
>>>>
>>>> Based on 'clk-next'. Build tested.
>>>>
>>>>   drivers/clk/qcom/common.c | 1 +
>>>>   1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
>>>> index cfab7b400381..df004ead1bef 100644
>>>> --- a/drivers/clk/qcom/common.c
>>>> +++ b/drivers/clk/qcom/common.c
>>>> @@ -157,6 +157,7 @@ static int _qcom_cc_register_board_clk(struct device *dev, const char *path,
>>>>   		init_data.name = path;
>>>>   		init_data.ops = &clk_fixed_rate_ops;
>>>> +		init_data.num_parents = 0;
>>> It seems like there was a initializer in the declaration but it was { } instead
>>> of { 0 }.
>>>
>>> Was the original intent to make this structure initialized to 0?  If so, perhaps
>>> it should be fixed above in the initializer.
>> yes, i think we intend to initialize the clock init data to 0, and thus
>> we should do that during declaration.
>> Will modify and re-spin the patch.
>>
> What's the error exactly? Do you have some call stack/crash that
> could be put in the commit text?

I got a crash dump from clk_register, when i was working on qmp phy
driver patches. This came when clk_init_data was not initilized.
So i had to explicitly assign num_parents to 0.

> It was my understanding that GCC allows braces without anything
> inside to initialize structures to 0, so I'm confused what's
> wrong here.

You are right. My understanding, that we need to initialize a structure
with {0}, was incomplete.
We don't need this patch.

> If this is actually a problem then we have other
> places to fix this.
>
>   $ git grep "clk_init_data.*{ *}"
>   drivers/clk/bcm/clk-bcm53573-ilp.c:     struct clk_init_data init = { };
>   drivers/clk/clk-gpio.c: struct clk_init_data init = {};
>   drivers/clk/clk-qoriq.c:        struct clk_init_data init = {};
>   drivers/clk/clk-rk808.c:        struct clk_init_data init = {};
>   drivers/clk/mediatek/clk-apmixed.c:     struct clk_init_data init = {};
>   drivers/clk/mediatek/clk-gate.c:        struct clk_init_data init = {};
>   drivers/clk/mediatek/clk-pll.c: struct clk_init_data init = {};
>   drivers/clk/qcom/common.c:      struct clk_init_data init_data = { };
>   drivers/gpu/drm/msm/dsi/pll/dsi_pll_28nm_8960.c:        struct clk_init_data bytediv_init = { };
>

Regards
Vivek

-- 
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project