[PATCH net-next 1/4] net: pse-pd: unlink the controller before freeing its PI data

[Carlo Szelinsky <github@szelinsky.de>]

pse_controller_unregister() frees the PI array before it takes the
controller off pse_controller_list. In that window of_pse_control_get()
can still find the controller and read the freed array, and so can
pse_isr() and the notification worker.

Disable the IRQ, take the controller off the list and stop the worker
first. Only then free the PI data.

Signed-off-by: Carlo Szelinsky <github@szelinsky.de>
---
 drivers/net/pse-pd/pse_core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index a5e6d7b26b9f..364acc025097 100644
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -1114,15 +1114,19 @@ EXPORT_SYMBOL_GPL(pse_controller_register);
  */
 void pse_controller_unregister(struct pse_controller_dev *pcdev)
 {
-	pse_flush_pw_ds(pcdev);
-	pse_release_pis(pcdev);
+	/* Stop the IRQ, new lookups and the worker before freeing pcdev->pi. */
 	if (pcdev->irq)
 		disable_irq(pcdev->irq);
-	cancel_work_sync(&pcdev->ntf_work);
-	kfifo_free(&pcdev->ntf_fifo);
+
 	mutex_lock(&pse_list_mutex);
 	list_del(&pcdev->list);
 	mutex_unlock(&pse_list_mutex);
+
+	cancel_work_sync(&pcdev->ntf_work);
+
+	pse_flush_pw_ds(pcdev);
+	pse_release_pis(pcdev);
+	kfifo_free(&pcdev->ntf_fifo);
 }
 EXPORT_SYMBOL_GPL(pse_controller_unregister);
 
-- 
2.43.0