linux-kernel - Re: [PATCH 2/2] power: charger-manager: Fix a bug when it unregisters notifier block of extcon.

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Date:	Wed, 26 Jun 2013 10:22:28 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	jonghwa3.lee@...sung.com
Cc:	Anton Vorontsov <anton.vorontsov@...aro.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Myungjoo Ham <myungjoo.ham@...sung.com>
Subject: Re: [PATCH 2/2] power: charger-manager: Fix a bug when it unregisters
 notifier block of extcon.

On 06/26/2013 10:19 AM, jonghwa3.lee@...sung.com wrote:
> Hi,
> On 2013Гт 06Пљ 25РЯ 22:34, Chanwoo Choi wrote:
> 
>> On Tue, Jun 25, 2013 at 2:02 PM, Jonghwa Lee <jonghwa3.lee@...sung.com
>> <mailto:jonghwa3.lee@...sung.com>> wrote:
>>
>>     This patch prevents NULL pointer error cauesed by unregistering unregistered
>>     exton notifier block. At the probing time of charger manager, it tries to
>>     remove extcon notifier block when it fails to initialize them. It has to be
>>     applied for only registered one. Otherwise, it'd make kernel panic. To make it
>>     work right, it checks extcon_specific_cable_nb's extcon_dev node. If extcon
>>     cable notifier block was registered successfully, it has proper extcon_dev
>>     pointer if not so it has NULL pointer.
>>
>>     Signed-off-by: Jonghwa Lee <jonghwa3.lee@...sung.com
>>     <mailto:jonghwa3.lee@...sung.com>>
>>     Signed-off-by: Myungjoo Ham <myungjoo.ham@...sung.com
>>     <mailto:myungjoo.ham@...sung.com>>
>>     ---
>>      drivers/power/charger-manager.c |    4 +++-
>>      1 file changed, 3 insertions(+), 1 deletion(-)
>>
>>     diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
>>     index 7d1bcde..c55a7dc 100644
>>     --- a/drivers/power/charger-manager.c
>>     +++ b/drivers/power/charger-manager.c
>>     @@ -1666,7 +1666,9 @@ err_reg_extcon:
>>                     charger = &desc->charger_regulators[i];
>>                     for (j = 0; j < charger->num_cables; j++) {
>>                             struct charger_cable *cable = &charger->cables[j];
>>     -                       extcon_unregister_interest(&cable->extcon_dev);
>>     +                       /* Remove notifier block if only edev exists */
>>     +                       if (cable->extcon_dev.edev)
>>     +                               extcon_unregister_interest(&cable->extcon_dev);
>>                     }
>>
>>                     regulator_put(desc->charger_regulators[i].consumer);
>>     --
>>     1.7.9.5
>>
>>
>> The charger-manager.c call extcon_unregister_interest() in
>> charger_manager_remove() function.
>> So, you should to fix it on charger_manager_remove() to remove NULL pointer error.
>>
> 
> 
> When .remove() callback function is called, there is no unregistered cable
> notifier block. Because all extcon notifier block would be registered at probing
> time, and if it is failed the probing can't be achieved. So I think it doesn't
> need to fix .remove() callback function as like above.
> 
> Thank you for reviewing.
> 
> Best regards,
> Jonghwa.
> 
> 
>> Acked-by: Chanwoo Choi <cw00.choi@...sung.com <mailto:cw00.choi@...sung.com>>
>>
>> Thanks,
>> Chanwoo Choi
>>  
> 

OK, I agree your opinion.

Acked-by: Chanwoo Choi <cw00.choi@...sung.com>

Thanks,
Chanwoo Choi

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