[PATCH net 1/2] net: pse-pd: disable IRQ before freeing PI data in unregister

[Carlo Szelinsky <github@szelinsky.de>]

pse_controller_unregister() frees the PI array via pse_release_pis()
before disabling the controller IRQ. The threaded IRQ handler pse_isr()
walks pcdev->pi[] (via pse_set_config_isr() and
regulator_notifier_call_chain() on pcdev->pi[i].rdev), so an interrupt
arriving in the window between pse_release_pis() and disable_irq()
dereferences freed memory.

Disable the IRQ first, then release the PI array. cancel_work_sync()
for the notification worker stays after pse_release_pis(): the worker
only touches the kfifo and the pse_control list, not pcdev->pi.

Fixes: ffef61d6d273 ("net: pse-pd: Add support for budget evaluation strategies")
Signed-off-by: Carlo Szelinsky <github@szelinsky.de>
---
 drivers/net/pse-pd/pse_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index 87aa4f4e9724..17f45e4b672b 100644
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -1115,9 +1115,9 @@ EXPORT_SYMBOL_GPL(pse_controller_register);
 void pse_controller_unregister(struct pse_controller_dev *pcdev)
 {
 	pse_flush_pw_ds(pcdev);
-	pse_release_pis(pcdev);
 	if (pcdev->irq)
 		disable_irq(pcdev->irq);
+	pse_release_pis(pcdev);
 	cancel_work_sync(&pcdev->ntf_work);
 	kfifo_free(&pcdev->ntf_fifo);
 	mutex_lock(&pse_list_mutex);
-- 
2.43.0