[PATCH v2 11/11] rpmsg: fix kfree() of static memory on setting driver_override

[Krzysztof Kozlowski]

The driver_override field from platform driver should not be initialized
from static memory (string literal) because the core later kfree() it,
for example when driver_override is set via sysfs.

Use dedicated helper to set driver_override properly.

Fixes: 950a7388f02b ("rpmsg: Turn name service into a stand alone driver")
Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface")
Cc: <stable at vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski at canonical.com>
---
 drivers/rpmsg/rpmsg_internal.h | 13 +++++++++++--
 drivers/rpmsg/rpmsg_ns.c       | 14 ++++++++++++--
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index b1245d3ed7c6..c7bd0a3c802d 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -92,10 +92,19 @@ int rpmsg_release_channel(struct rpmsg_device *rpdev,
  */
 static inline int rpmsg_chrdev_register_device(struct rpmsg_device *rpdev)
 {
+	int ret;
+
 	strcpy(rpdev->id.name, "rpmsg_chrdev");
-	rpdev->driver_override = "rpmsg_chrdev";
+	ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
+				  "rpmsg_chrdev");
+	if (ret)
+		return ret;
+
+	ret = rpmsg_register_device(rpdev);
+	if (ret)
+		kfree(rpdev->driver_override);
 
-	return rpmsg_register_device(rpdev);
+	return ret;
 }
 
 #endif
diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
index 762ff1ae279f..1c9f9cf065b0 100644
--- a/drivers/rpmsg/rpmsg_ns.c
+++ b/drivers/rpmsg/rpmsg_ns.c
@@ -20,12 +20,22 @@
  */
 int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
 {
+	int ret;
+
 	strcpy(rpdev->id.name, "rpmsg_ns");
-	rpdev->driver_override = "rpmsg_ns";
+	ret = driver_set_override(&rpdev->dev, &rpdev->driver_override,
+				  "rpmsg_ns");
+	if (ret)
+		return ret;
+
 	rpdev->src = RPMSG_NS_ADDR;
 	rpdev->dst = RPMSG_NS_ADDR;
 
-	return rpmsg_register_device(rpdev);
+	ret = rpmsg_register_device(rpdev);
+	if (ret)
+		kfree(rpdev->driver_override);
+
+	return ret;
 }
 EXPORT_SYMBOL(rpmsg_ns_register_device);
 
-- 
2.32.0