[PATCH 6.1 093/482] pps: clients: gpio: fix interrupt handling order in remove path

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eliav Farber <redacted>

[ Upstream commit 6bca1e955830808dc90e0506b2951b4256b81bbb ]

The interrupt handler in pps_gpio_probe() is registered after calling
pps_register_source() using devm_request_irq(). However, in the
corresponding remove function, pps_unregister_source() is called before
the IRQ is freed, since devm-managed resources are released after the
remove function completes.

This creates a potential race condition where an interrupt may occur
after the PPS source is unregistered but before the handler is removed,
possibly leading to a kernel panic.

To prevent this, switch from devm-managed IRQ registration to manual
management by using request_irq() and calling free_irq() explicitly in
the remove path before unregistering the PPS source. This ensures the
interrupt handler is safely removed before deactivating the PPS source.

Signed-off-by: Eliav Farber <redacted>
Link: https://lore.kernel.org/r/20250527053355.37185-1-farbere@amazon.com (local)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pps/clients/pps-gpio.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index bf3b6f1aa984..41e1fdbcda16 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c

@@ -206,8 +206,8 @@ static int pps_gpio_probe(struct platform_device *pdev)
 	}
 
 	/* register IRQ interrupt handler */
-	ret = devm_request_irq(dev, data->irq, pps_gpio_irq_handler,
-			get_irqf_trigger_flags(data), data->info.name, data);
+	ret = request_irq(data->irq, pps_gpio_irq_handler,
+			  get_irqf_trigger_flags(data), data->info.name, data);
 	if (ret) {
 		pps_unregister_source(data->pps);
 		dev_err(dev, "failed to acquire IRQ %d\n", data->irq);

@@ -224,6 +224,7 @@ static int pps_gpio_remove(struct platform_device *pdev)
 {
 	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
 
+	free_irq(data->irq, data);
 	pps_unregister_source(data->pps);
 	del_timer_sync(&data->echo_timer);
 	/* reset echo pin in any case */

-- 
2.39.5