[PATCH] xenbus: don't free other end details too early

[PATCH] xenbus: don't free other end details too early

[Jan Beulich]

[-- Attachment #1: Type: text/plain, Size: 923 bytes --]

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;
 }




[-- Attachment #2: linux-3.3-rc6-xenbus-remove-details.patch --]
[-- Type: text/plain, Size: 917 bytes --]

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;
 }

Re: [PATCH] xenbus: don't free other end details too early

[Konrad Rzeszutek Wilk]

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;
>  }