RE: [PATCH v2] Drivers: hv: vmbus: incorrect device name is printedwhen child device is unregistered

From: KY Srinivasan
Date: Tue Jun 25 2013 - 14:16:51 EST




> -----Original Message-----
> From: Fernando Soto [mailto:fsoto@xxxxxxxxxxxxxxxxxxx]
> Sent: Friday, June 14, 2013 7:14 PM
> To: linux-kernel@xxxxxxxxxxxxxxx
> Cc: Haiyang Zhang; KY Srinivasan; Greg KH (gregkh@xxxxxxxxxxxxxxxxxxx)
> Subject: [PATCH v2] Drivers: hv: vmbus: incorrect device name is printed when
> child device is unregistered
>
> From: Fernando Soto <fsoto@xxxxxxxxxxxxxxxxxxx>
> Please CC me, I am not subscribed to the list.
>
> Whenever a device is unregistered in vmbus_device_unregister
> (drivers/hv/vmbus_drv.c), the device name in the log message may contain
> garbage as the memory has already been freed by the time pr_info is called. Log
> example:
> [ 3149.170475] hv_vmbus: child device àõsèè0_5 unregistered
>
> By logging the message just before calling device_unregister, the correct device
> name is printed:
> [ 3145.034652] hv_vmbus: child device vmbus_0_5 unregistered
>
> Also changing register & unregister messages to debug to avoid unnecessarily
> cluttering the kernel log.
>
> Signed-off-by: Fernando M Soto <fsoto@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> --- linux-3.10-rc5/drivers/hv/vmbus_drv.c.orig 2013-06-13 19:20:55.359511352 -
> 0400
> +++ linux-3.10-rc5/drivers/hv/vmbus_drv.c 2013-06-14 19:00:21.722105728 -
> 0400
> @@ -686,7 +686,7 @@ int vmbus_device_register(struct hv_devi
> if (ret)
> pr_err("Unable to register child device\n");
> else
> - pr_info("child device %s registered\n",
> + pr_debug("child device %s registered\n",
> dev_name(&child_device_obj->device));
>
> return ret;
> @@ -698,14 +698,14 @@ int vmbus_device_register(struct hv_devi
> */
> void vmbus_device_unregister(struct hv_device *device_obj)
> {
> + pr_debug("child device %s unregistered\n",
> + dev_name(&device_obj->device));
> +
> /*
> * Kick off the process of unregistering the device.
> * This will call vmbus_remove() and eventually vmbus_device_release()
> */
> device_unregister(&device_obj->device);
> -
> - pr_info("child device %s unregistered\n",
> - dev_name(&device_obj->device));
> }
>
>
> --
>


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