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From:   Michael Grzeschik <m.grzeschik@pengutronix.de>
To:     a.zummo@towertech.it, alexandre.belloni@free-electrons.com
Cc:     linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, linux@roeck-us.net, jdelvare@suse.com,
        kernel@pengutronix.de, Denis.Osterland@diehl.com
Subject: [PATCH 3/4] rtc: isl1208: enable interrupt after context preparation
Date:   Tue, 23 Jan 2018 13:18:00 +0100
Message-Id: <20180123121801.4214-4-m.grzeschik@pengutronix.de>
In-Reply-To: <20180123121801.4214-1-m.grzeschik@pengutronix.de>
References: <20180123121801.4214-1-m.grzeschik@pengutronix.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The interrupt handler got enabled very early. If the interrupt cause is
triggering immediately before the context is fully prepared. This can
lead to undefined behaviour. Therefor we move the interrupt enable code
to the end of the probe function.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Denis Osterland <Denis.Osterland@diehl.com>
---
 drivers/rtc/rtc-isl1208.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
index c8b4953482296..a13a4ba79004d 100644
--- a/drivers/rtc/rtc-isl1208.c
+++ b/drivers/rtc/rtc-isl1208.c
@@ -635,23 +635,6 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (isl1208_i2c_validate_client(client) < 0)
 		return -ENODEV;
 
-	if (client->irq > 0) {
-		rc = devm_request_threaded_irq(&client->dev, client->irq, NULL,
-					       isl1208_rtc_interrupt,
-					       IRQF_SHARED | IRQF_ONESHOT,
-					       isl1208_driver.driver.name,
-					       client);
-		if (!rc) {
-			device_init_wakeup(&client->dev, 1);
-			enable_irq_wake(client->irq);
-		} else {
-			dev_err(&client->dev,
-				"Unable to request irq %d, no alarm support\n",
-				client->irq);
-			client->irq = 0;
-		}
-	}
-
 	rtc = devm_rtc_device_register(&client->dev, isl1208_driver.driver.name,
 				  &isl1208_rtc_ops,
 				  THIS_MODULE);
@@ -674,6 +657,23 @@ isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (rc)
 		return rc;
 
+	if (client->irq > 0) {
+		rc = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+					       isl1208_rtc_interrupt,
+					       IRQF_SHARED | IRQF_ONESHOT,
+					       isl1208_driver.driver.name,
+					       client);
+		if (!rc) {
+			device_init_wakeup(&client->dev, 1);
+			enable_irq_wake(client->irq);
+		} else {
+			dev_err(&client->dev,
+				"Unable to request irq %d, no alarm support\n",
+				client->irq);
+			client->irq = 0;
+		}
+	}
+
 	return 0;
 }
 
-- 
2.11.0