[PATCH 4.2.y-ckt 041/268] coresight: checking for NULL string in coresight_name_match()

[Kamal Mostafa]

4.2.8-ckt3 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Mathieu Poirier <mathieu.poirier at linaro.org>

commit fadf3a44e974b030e7145218ad1ab25e3ef91738 upstream.

Connection child names associated to ports can sometimes be NULL,
which is the case when booting a system on QEMU or when the Coresight
power domain isn't switched on.

This patch is adding a check to make sure a NULL string isn't fed
to strcmp(), something that avoid crashing the system.

Reported-by: Tyler Baker <tyler.baker at linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier at linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/hwtracing/coresight/coresight.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 894531d..046144f 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -543,7 +543,7 @@ static int coresight_name_match(struct device *dev, void *data)
 	to_match = data;
 	i_csdev = to_coresight_device(dev);
 
-	if (!strcmp(to_match, dev_name(&i_csdev->dev)))
+	if (to_match && !strcmp(to_match, dev_name(&i_csdev->dev)))
 		return 1;
 
 	return 0;
-- 
1.9.1