[PATCH 06/11] rtc: max8925: Initialize drvdata before registering device

[John Stultz]

Commit f44f7f96a20 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
CC: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: rtc-linux@xxxxxxxxxxxxxxxx
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
 drivers/rtc/rtc-max8925.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-max8925.c b/drivers/rtc/rtc-max8925.c
index 20494b5..3bc046f 100644
--- a/drivers/rtc/rtc-max8925.c
+++ b/drivers/rtc/rtc-max8925.c
@@ -258,6 +258,8 @@ static int __devinit max8925_rtc_probe(struct platform_device *pdev)
 	}
 
 	dev_set_drvdata(&pdev->dev, info);
+	/* XXX - isn't this redundant? */
+	platform_set_drvdata(pdev, info);
 
 	info->rtc_dev = rtc_device_register("max8925-rtc", &pdev->dev,
 					&max8925_rtc_ops, THIS_MODULE);
@@ -267,10 +269,9 @@ static int __devinit max8925_rtc_probe(struct platform_device *pdev)
 		goto out_rtc;
 	}
 
-	platform_set_drvdata(pdev, info);
-
 	return 0;
 out_rtc:
+	platform_set_drvdata(pdev, NULL);
 	free_irq(chip->irq_base + MAX8925_IRQ_RTC_ALARM0, info);
 out_irq:
 	kfree(info);
-- 
1.7.3.2.146.gca209

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/