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

From: Konrad Rzeszutek Wilk
Date: Wed Mar 14 2012 - 12:37:46 EST


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@xxxxxxxx>
>
> ---
> 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@xxxxxxxx>
>
> ---
> 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;
> }

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