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Date: Wed, 14 Mar 2012 12:33:08 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>, xen-devel <xen-devel@lists.xen.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] xenbus: don't free other end details too early
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On Mon, Mar 05, 2012 at 05:11:31PM +0000, Jan Beulich wrote:
> The individual drivers' remove functions could legitimately attempt to
> access this information (for logging messages if nothing else). Note
> that I did not in fact observe a problem anywhere, but I came across
> this while looking into the reasons for what turned out to need the
> fix at https://lkml.org/lkml/2012/3/5/336 to vsprintf().

applied.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> ---
>  drivers/xen/xenbus/xenbus_probe.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> --- 3.3-rc6/drivers/xen/xenbus/xenbus_probe.c
> +++ 3.3-rc6-xenbus-remove-details/drivers/xen/xenbus/xenbus_probe.c
> @@ -257,11 +257,12 @@ int xenbus_dev_remove(struct device *_de
>  	DPRINTK("%s", dev->nodename);
>  
>  	free_otherend_watch(dev);
> -	free_otherend_details(dev);
>  
>  	if (drv->remove)
>  		drv->remove(dev);
>  
> +	free_otherend_details(dev);
> +
>  	xenbus_switch_state(dev, XenbusStateClosed);
>  	return 0;
>  }
> 
> 
> 

> The individual drivers' remove functions could legitimately attempt to
> access this information (for logging messages if nothing else). Note
> that I did not in fact observe a problem anywhere, but I came across
> this while looking into the reasons for what turned out to need the
> fix at https://lkml.org/lkml/2012/3/5/336 to vsprintf().
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> ---
>  drivers/xen/xenbus/xenbus_probe.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> --- 3.3-rc6/drivers/xen/xenbus/xenbus_probe.c
> +++ 3.3-rc6-xenbus-remove-details/drivers/xen/xenbus/xenbus_probe.c
> @@ -257,11 +257,12 @@ int xenbus_dev_remove(struct device *_de
>  	DPRINTK("%s", dev->nodename);
>  
>  	free_otherend_watch(dev);
> -	free_otherend_details(dev);
>  
>  	if (drv->remove)
>  		drv->remove(dev);
>  
> +	free_otherend_details(dev);
> +
>  	xenbus_switch_state(dev, XenbusStateClosed);
>  	return 0;
>  }