[SRU][Precise][PATCH 1/1] Drivers: hv: vmbus: incorrect device name is printed when child device is unregistered

Joseph Salisbury joseph.salisbury at canonical.com
Tue Mar 3 19:53:38 UTC 2015

From: Fernando Soto <fsoto at bluecatnetworks.com>

BugLink: http://bugs.launchpad.net/bugs/1417313

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 at bluecatnetworks.com>
Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit 84672369ffb98a51d4ddf74c20a23636da3ad615)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
 drivers/hv/vmbus_drv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 10619b3..1ec309d 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -681,7 +681,7 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 	if (ret)
 		pr_err("Unable to register child device\n");
-		pr_info("child device %s registered\n",
+		pr_debug("child device %s registered\n",
 	return ret;
@@ -693,14 +693,14 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 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()
-	pr_info("child device %s unregistered\n",
-		dev_name(&device_obj->device));

More information about the kernel-team mailing list