linux-kernel - Re: [PATCH] ssb:: use put_device() if device

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Message-ID: <5AA01E5E.8070002@gmail.com>
Date:   Wed, 7 Mar 2018 22:46:14 +0530
From:   arvindY <arvind.yadav.cs@...il.com>
To:     Michael Büsch <m@...s.ch>
Cc:     linux-kernel@...r.kernel.org, linux-wireless@...r.kernel.org
Subject: Re: [PATCH] ssb:: use put_device() if device_register fail



On Wednesday 07 March 2018 10:17 PM, Michael Büsch wrote:
> On Wed,  7 Mar 2018 15:31:30 +0530
> Arvind Yadav <arvind.yadav.cs@...il.com> wrote:
>
>> if device_register() returned an error! Always use put_device()
>> to give up the reference initialized.
>>
>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@...il.com>
>> ---
>>   drivers/ssb/main.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
>> index 65420a9..c4449e0 100644
>> --- a/drivers/ssb/main.c
>> +++ b/drivers/ssb/main.c
>> @@ -521,6 +521,7 @@ static int ssb_devices_register(struct ssb_bus *bus)
>>   			ssb_err("Could not register %s\n", dev_name(dev));
>>   			/* Set dev to NULL to not unregister
>>   			 * dev on error unwinding. */
>> +			put_device(dev);
>>   			sdev->dev = NULL;
>>   			kfree(devwrap);
>>   			goto error;
>
> I don't think this is correct.
> The dev structure is allocated as part of devwrap, which is freed here.
>
> Why do you think we need put_device here?
>
Yes this patch is not correct, We must not use kfree() after you called 
device_register() (even
if it was not successful!) -- see the comment for device_register().
I will delete kfree() and send updated patch.

~arvind