linux-kernel - [PATCH] pps: clients: gpio: fix interrupt handling order in remove path

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250527053355.37185-1-farbere@amazon.com>
Date: Tue, 27 May 2025 05:33:55 +0000
From: Eliav Farber <farbere@...zon.com>
To: <giometti@...eenne.com>, <gregkh@...uxfoundation.org>,
	<mschmidt@...hat.com>, <calvin@...nvd.org>, <u.kleine-koenig@...gutronix.de>,
	<tglx@...utronix.de>, <farbere@...zon.com>, <linux-kernel@...r.kernel.org>
CC: <jonnyc@...zon.com>
Subject: [PATCH] pps: clients: gpio: fix interrupt handling order in remove path

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@...zon.com>
---
 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 374ceefd6f2a..2866636b0554 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c
@@ -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 */
-- 
2.47.1