[PATCH v4 08/16] firmware: arm_scmi: Unregister device notifier before IDR teardown

[Sudeep Holla <sudeep.holla@kernel.org>]

The requested-devices notifier looks up protocol fwnodes from the
active_protocols IDR. During remove, unregister the notifier before
releasing and destroying active_protocols so no notifier callback can race
with the IDR teardown.

Keep the bus notifier registered until after the protocol state is torn
down, matching the existing remove ordering for SCMI bus users.

Fixes: 53b8c25df708 ("firmware: arm_scmi: Add common notifier helpers")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
---
 drivers/firmware/arm_scmi/driver.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 41f1b2c49521..67267507ea1d 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -3403,6 +3403,9 @@ static void scmi_remove(struct platform_device *pdev)
 	list_del(&info->node);
 	mutex_unlock(&scmi_list_mutex);
 
+	blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
+					   &info->dev_req_nb);
+
 	/* Stop transport callbacks before tearing down notifications. */
 	scmi_cleanup_txrx_channels(info);
 	scmi_notification_exit(&info->handle);
@@ -3415,8 +3418,6 @@ static void scmi_remove(struct platform_device *pdev)
 		of_node_put(child);
 	idr_destroy(&info->active_protocols);
 
-	blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
-					   &info->dev_req_nb);
 	bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
 
 	ida_free(&scmi_id, info->id);

-- 
2.43.0