[PATCH] power: supply: bq24190: stop IRQ and work before supply removal

[PATCH] power: supply: bq24190: stop IRQ and work before supply removal

[Yaohan Li]

bq24190_remove() unregisters its power supplies while a managed IRQ
handler and input_current_limit_work may still access them. The
managed IRQ is only released after remove() returns, so stopping the
supplies first leaves a window for a callback to use freed memory.

Release and synchronize the IRQ before unregistering the supplies,
and cancel the delayed current-limit work. Cancel the work once more
after unregistering to drain any instance requeued by an in-flight
power-supply callback.

A KASAN test with a simulated I2C device and the in-tree charger
driver reproduced the race during removal. The same test completed
without the use-after-free after the change.

Fixes: 4f73a52df7d28278 ("power: supply: bq24190: Avoid rescheduling after cancelling work")
Assisted-by: ZCode:GLM-4
Signed-off-by: Yaohan Li <shunsheng1218@gmail.com>
---
 drivers/power/supply/bq24190_charger.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/power/supply/bq24190_charger.c b/drivers/power/supply/bq24190_charger.c
index 7a5867dd74c23..fd0ea5385f0dd 100644
--- a/drivers/power/supply/bq24190_charger.c
+++ b/drivers/power/supply/bq24190_charger.c
@@ -2265,9 +2265,24 @@ static void bq24190_remove(struct i2c_client *client)
 		dev_warn(bdi->dev, "pm_runtime_get failed: %i\n", error);
 
 	bq24190_register_reset(bdi);
+
+	/*
+	 * The IRQ handler and the input current limit work both access the
+	 * power supplies. Stop them before the supplies are unregistered
+	 * and freed below: the devm cleanup only runs after .remove() has
+	 * returned. The second cancel catches work re-queued by an
+	 * external_power_changed() callback which was still running while
+	 * the supplies were unregistered (the work has a 300 ms delay).
+	 */
+	devm_free_irq(bdi->dev, client->irq, bdi);
+	cancel_delayed_work_sync(&bdi->input_current_limit_work);
+
 	if (bdi->battery)
 		power_supply_unregister(bdi->battery);
 	power_supply_unregister(bdi->charger);
+
+	cancel_delayed_work_sync(&bdi->input_current_limit_work);
+
 	if (error >= 0)
 		pm_runtime_put_sync(bdi->dev);
 	pm_runtime_dont_use_autosuspend(bdi->dev);
-- 
2.34.1