[PATCH] mfd: twl6040: fix IRQ action memory leaks during teardown

[Guangshuo Li <lgs201920130244@gmail.com>]

twl6040_remove() currently removes the regmap IRQ chip before
removing the MFD child devices. This destroys the IRQ mappings
before the child drivers can release their interrupt handlers.

The parent driver also registers READY and thermal interrupt
handlers using devm_request_threaded_irq(). These handlers are
normally released by device-managed cleanup after remove returns,
when the corresponding IRQ descriptors have already been removed.

Consequently, free_irq() cannot find the IRQ descriptors and the
allocated struct irqaction objects are not freed. The associated
IRQ threads also cannot be stopped through the normal cleanup path.

The probe error paths have a similar issue, as they destroy the IRQ
chip before the device-managed IRQ handlers are released.

Remove the MFD child devices first, then explicitly free the
parent's READY and thermal IRQ handlers using devm_free_irq()
before removing the regmap IRQ chip.

Also update the probe error paths to release successfully requested
IRQs before destroying their mappings.

This issue was found by our static analysis tool under development.

Fixes: ab7edb149c75 ("mfd: twl6040: Convert to use regmap_irq")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/mfd/twl6040.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
index 562a0f939f6e..7b05d21cd17d 100644
--- a/drivers/mfd/twl6040.c
+++ b/drivers/mfd/twl6040.c
@@ -745,7 +745,7 @@ static int twl6040_probe(struct i2c_client *client)
 					"twl6040_irq_th", twl6040);
 	if (ret) {
 		dev_err(twl6040->dev, "Thermal IRQ request failed: %d\n", ret);
-		goto readyirq_err;
+		goto thirq_err;
 	}
 
 	/*
@@ -791,10 +791,14 @@ static int twl6040_probe(struct i2c_client *client)
 	ret = mfd_add_devices(&client->dev, -1, twl6040->cells, children,
 			      NULL, 0, NULL);
 	if (ret)
-		goto readyirq_err;
+		goto mfd_err;
 
 	return 0;
 
+mfd_err:
+	devm_free_irq(twl6040->dev, twl6040->irq_th, twl6040);
+thirq_err:
+	devm_free_irq(twl6040->dev, twl6040->irq_ready, twl6040);
 readyirq_err:
 	regmap_del_irq_chip(twl6040->irq, twl6040->irq_data);
 gpio_err:
@@ -809,9 +813,10 @@ static void twl6040_remove(struct i2c_client *client)
 	if (twl6040->power_count)
 		twl6040_power(twl6040, 0);
 
-	regmap_del_irq_chip(twl6040->irq, twl6040->irq_data);
-
 	mfd_remove_devices(&client->dev);
+	devm_free_irq(twl6040->dev, twl6040->irq_th, twl6040);
+	devm_free_irq(twl6040->dev, twl6040->irq_ready, twl6040);
+	regmap_del_irq_chip(twl6040->irq, twl6040->irq_data);
 
 	regulator_bulk_disable(TWL6040_NUM_SUPPLIES, twl6040->supplies);
 }
-- 
2.43.0