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

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Message-ID: <20131129205628.GA20144@pd.tnic>
Date:	Fri, 29 Nov 2013 21:56:28 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Levente Kurusa <levex@...ux.com>
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

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...?

> Signed-off-by: Levente Kurusa <levex@...ux.com>
> ---
>  arch/x86/kernel/cpu/mcheck/mce.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index b3218cd..a389c1d 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -2272,8 +2272,10 @@ static int mce_device_create(unsigned int cpu)
>  	dev->release = &mce_device_release;
> 
>  	err = device_register(dev);
> -	if (err)
> +	if (err) {
> +		put_device(dev);
>  		return err;
> +	}

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.

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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