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Subject[PATCH 01/11] rtc: mxc: Initialize drvdata before registering device
Date
From: Wolfram Sang <w.sang@pengutronix.de>

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: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
[fixed up commit log -jstultz]
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/rtc/rtc-mxc.c | 19 +++++++++++--------
1 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/rtc/rtc-mxc.c b/drivers/rtc/rtc-mxc.c
index 826ab64..d814417 100644
--- a/drivers/rtc/rtc-mxc.c
+++ b/drivers/rtc/rtc-mxc.c
@@ -418,14 +418,6 @@ static int __init mxc_rtc_probe(struct platform_device *pdev)
goto exit_put_clk;
}

- rtc = rtc_device_register(pdev->name, &pdev->dev, &mxc_rtc_ops,
- THIS_MODULE);
- if (IS_ERR(rtc)) {
- ret = PTR_ERR(rtc);
- goto exit_put_clk;
- }
-
- pdata->rtc = rtc;
platform_set_drvdata(pdev, pdata);

/* Configure and enable the RTC */
@@ -438,8 +430,19 @@ static int __init mxc_rtc_probe(struct platform_device *pdev)
pdata->irq = -1;
}

+ rtc = rtc_device_register(pdev->name, &pdev->dev, &mxc_rtc_ops,
+ THIS_MODULE);
+ if (IS_ERR(rtc)) {
+ ret = PTR_ERR(rtc);
+ goto exit_clr_drvdata;
+ }
+
+ pdata->rtc = rtc;
+
return 0;

+exit_clr_drvdata:
+ platform_set_drvdata(pdev, NULL);
exit_put_clk:
clk_disable(pdata->clk);
clk_put(pdata->clk);
--
1.7.3.2.146.gca209


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