linux-kernel - Re: [PATCH] x86: mcheck: call put_device on device

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Message-ID: <52999419.7040600@linux.com>
Date:	Sat, 30 Nov 2013 08:30:33 +0100
From:	Levente Kurusa <levex@...ux.com>
To:	Borislav Petkov <bp@...en8.de>
CC:	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Tony Luck <tony.luck@...el.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	EDAC <linux-edac@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: mcheck: call put_device on device_register failure

2013-11-29 21:56, Borislav Petkov:
> On Fri, Nov 29, 2013 at 09:28:48PM +0100, Levente Kurusa wrote:
>> This patch adds a call to put_device() when the device_register()
>> call has failed. This is required so that the last reference to the
>> device is given up.
> 
> I'd assume this is not something you're actually hitting but have caught
> this by code staring...?
> 

Yup, I have been staring at it.

> If we're going to do this, I'd also like to see you add another label
> after device_unregister(dev) which also kfrees dev because apparently
> we're not doing that either.
> 

No, if the call to put_device gives up the last reference to the device,
then device_release gets called which in turn frees the memory associated with it.
In this case, mce_device_release() will get called, which is just a simple kfree call.

-- 
Regards,
Levente Kurusa
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