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From: Tilman Schmidt <tilman@imap.cc>
To: Paul Bolle <pebolle@tiscali.nl>,
	Peter Hurley <peter@hurleysoftware.com>,
	Sasha Levin <sasha.levin@oracle.com>
Cc: isdn@linux-pingi.de, davem@davemloft.net,
	gigaset307x-common@lists.sourceforge.net,
	LKML <linux-kernel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	syzkaller <syzkaller@googlegroups.com>
Subject: Re: gigaset: freeing an active object
Date: Mon, 7 Dec 2015 10:27:03 +0100	[thread overview]
Message-ID: <566550E7.80801@imap.cc> (raw)
In-Reply-To: <1449432742.2515.20.camel@tiscali.nl>

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Am 06.12.2015 um 21:12 schrieb Paul Bolle:
> On zo, 2015-12-06 at 16:29 +0100, Tilman Schmidt wrote:
>> So the solution might be as simple as moving the kfree() call from
>> gigaset_freecshw() to gigaset_device_release(). Something like this:
>>
>> --- a/drivers/isdn/gigaset/ser-gigaset.c
>> +++ b/drivers/isdn/gigaset/ser-gigaset.c
>> @@ -370,19 +370,18 @@ static void gigaset_freecshw(struct cardstate
>> *cs)
>>         tasklet_kill(&cs->write_tasklet);
>>         if (!cs->hw.ser)
>>                 return;
>> -       dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
>>         platform_device_unregister(&cs->hw.ser->dev);
>> -       kfree(cs->hw.ser);
>> -       cs->hw.ser = NULL;
>>  }
>>
>>  static void gigaset_device_release(struct device *dev)
>>  {
>> -       struct platform_device *pdev = to_platform_device(dev);
>> +       struct cardstate *cs = dev_get_drvdata(dev);
>>
>> -       /* adapted from platform_device_release() in drivers/base/platform.c */
>> -       kfree(dev->platform_data);
>> -       kfree(pdev->resource);
>> +       if (!cs)
>> +               return;
>> +       dev_set_drvdata(dev, NULL);
>> +       kfree(cs->hw.ser);
>> +       cs->hw.ser = NULL;
>>  }
> 
> This solution assumes that the struct platform_device is moved out of
> the struct ser_cardstate, doesn't it? In other words, this is something
> to do on top of my (draft) patch.

No, that wasn't my intention. I thought of that solution as an
alternative, not an increment to your patch.

> Otherwise we'd still be freeing memory
> managed through reference counting.

Now I#m confused. I thought by following Peter's suggestion to put the
kfree() in the release method we'd avoid just that.

Regards,
Tilman

-- 
Tilman Schmidt                              E-Mail: tilman@imap.cc
Bonn, Germany
Nous, on a des fleurs et des bougies pour nous protéger.


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  reply	other threads:[~2015-12-07  9:27 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-27 15:19 gigaset: freeing an active object Sasha Levin
2015-11-27 17:57 ` Paul Bolle
2015-11-27 18:15   ` Sasha Levin
2015-11-28  0:28     ` Paul Bolle
2015-11-28  1:20       ` Peter Hurley
2015-11-28  1:27         ` Sasha Levin
2015-11-29 14:36           ` Dmitry Vyukov
2015-11-29 15:30 ` Tilman Schmidt
2015-11-29 18:22   ` Peter Hurley
2015-11-29 18:38     ` Tilman Schmidt
2015-11-29 18:47     ` Tilman Schmidt
2015-11-29 20:26       ` Paul Bolle
2015-11-29 23:23         ` Paul Bolle
2015-11-30 18:01           ` Paul Bolle
2015-11-30 18:30             ` Tilman Schmidt
2015-11-30 21:07               ` Paul Bolle
2015-12-01  9:30                 ` Tilman Schmidt
2015-12-01 10:05                   ` Paul Bolle
2015-12-02 23:48             ` Peter Hurley
2015-12-06 13:31               ` Paul Bolle
2015-12-06 15:29                 ` Tilman Schmidt
2015-12-06 20:12                   ` Paul Bolle
2015-12-07  9:27                     ` Tilman Schmidt [this message]
2015-12-07 12:25                       ` Paul Bolle
2015-12-07 18:40                         ` Tilman Schmidt

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