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pps: clients: gpio: fix interrupt handling order in remove path

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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 <farbere@amazon.com>
Link: https://lore.kernel.org/r/20250527053355.37185-1-farbere@amazon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eliav Farber
2025-07-01 12:29:24 +02:00
committed by Greg Kroah-Hartman
parent bfb4cf9fb9
commit 6bca1e9558
1 changed files with 3 additions and 2 deletions
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drivers/pps/clients/pps-gpio.c
+3 -2
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@@ -210,8 +210,8 @@ 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);
@@ -228,6 +228,7 @@ static void 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);
timer_delete_sync(&data->echo_timer);
/* reset echo pin in any case */