[PATCH 2/2] firmware: arm_scmi: Unrequest devices if driver registration fails

scmi_driver_register() requests protocol devices before registering the
driver. If driver_register() fails, those requests remain in the global
IDR and retain pointers to the module's ID table. Once the failed module
load releases that storage, later request matching or SCMI device creation
can dereference the stale pointers.

Unrequest the complete protocol table before returning the registration
failure. At this point table registration succeeded, so every entry is
owned by the current registration attempt.

Fixes: d3cd7c525fd2 ("firmware: arm_scmi: Refactor protocol device creation")
Reported-by: Sashiko <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>
---
 drivers/firmware/arm_scmi/bus.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index af3d28717cd2..a86fa18fc5d2 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -395,10 +395,14 @@ int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
 	driver->driver.mod_name = mod_name;
 
 	retval = driver_register(&driver->driver);
-	if (!retval)
-		pr_debug("Registered new scmi driver %s\n", driver->name);
+	if (retval) {
+		scmi_protocol_table_unregister(driver->id_table);
+		return retval;
+	}
 
-	return retval;
+	pr_debug("Registered new scmi driver %s\n", driver->name);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(scmi_driver_register);
 
-- 
2.43.0