linux-kernel - [PATCH v2 1/2] gpio: em: remove the gpiochip before removing the irq domain

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Message-Id: <20190711082936.8706-1-brgl@bgdev.pl>
Date:   Thu, 11 Jul 2019 10:29:35 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Phil Reid <preid@...ctromag.com.au>
Cc:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        stable@...r.kernel.org
Subject: [PATCH v2 1/2] gpio: em: remove the gpiochip before removing the irq domain

From: Bartosz Golaszewski <bgolaszewski@...libre.com>

In commit 8764c4ca5049 ("gpio: em: use the managed version of
gpiochip_add_data()") we implicitly altered the ordering of resource
freeing: since gpiochip_remove() calls gpiochip_irqchip_remove()
internally, we now can potentially use the irq_domain after it was
destroyed in the remove() callback (as devm resources are freed after
remove() has returned).

Use devm_add_action_or_reset() to keep the ordering right and entirely
kill the remove() callback in the driver.

Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Fixes: 8764c4ca5049 ("gpio: em: use the managed version of gpiochip_add_data()")
Cc: stable@...r.kernel.org
Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
---
v1 -> v2:
- use devm_add_action_or_reset() to automatically remove the domain if
  the underlying devm_add_action() fails

 drivers/gpio/gpio-em.c | 33 +++++++++++++++------------------
 1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/gpio/gpio-em.c b/drivers/gpio/gpio-em.c
index b6af705a4e5f..a87951293aaa 100644
--- a/drivers/gpio/gpio-em.c
+++ b/drivers/gpio/gpio-em.c
@@ -259,6 +259,13 @@ static const struct irq_domain_ops em_gio_irq_domain_ops = {
 	.xlate	= irq_domain_xlate_twocell,
 };
 
+static void em_gio_irq_domain_remove(void *data)
+{
+	struct irq_domain *domain = data;
+
+	irq_domain_remove(domain);
+}
+
 static int em_gio_probe(struct platform_device *pdev)
 {
 	struct em_gio_priv *p;
@@ -333,39 +340,30 @@ static int em_gio_probe(struct platform_device *pdev)
 		return -ENXIO;
 	}
 
+	ret = devm_add_action_or_reset(&pdev->dev, em_gio_irq_domain_remove,
+				       p->irq_domain);
+	if (ret)
+		return ret;
+
 	if (devm_request_irq(&pdev->dev, irq[0]->start,
 			     em_gio_irq_handler, 0, name, p)) {
 		dev_err(&pdev->dev, "failed to request low IRQ\n");
-		ret = -ENOENT;
-		goto err1;
+		return -ENOENT;
 	}
 
 	if (devm_request_irq(&pdev->dev, irq[1]->start,
 			     em_gio_irq_handler, 0, name, p)) {
 		dev_err(&pdev->dev, "failed to request high IRQ\n");
-		ret = -ENOENT;
-		goto err1;
+		return -ENOENT;
 	}
 
 	ret = devm_gpiochip_add_data(&pdev->dev, gpio_chip, p);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to add GPIO controller\n");
-		goto err1;
+		return ret;
 	}
 
 	return 0;
-
-err1:
-	irq_domain_remove(p->irq_domain);
-	return ret;
-}
-
-static int em_gio_remove(struct platform_device *pdev)
-{
-	struct em_gio_priv *p = platform_get_drvdata(pdev);
-
-	irq_domain_remove(p->irq_domain);
-	return 0;
 }
 
 static const struct of_device_id em_gio_dt_ids[] = {
@@ -376,7 +374,6 @@ MODULE_DEVICE_TABLE(of, em_gio_dt_ids);
 
 static struct platform_driver em_gio_device_driver = {
 	.probe		= em_gio_probe,
-	.remove		= em_gio_remove,
 	.driver		= {
 		.name	= "em_gio",
 		.of_match_table = em_gio_dt_ids,
-- 
2.21.0