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rtc: pcap: Initialize drvdata before registering device 

Commit f44f7f96a2 ("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@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz 2011-05-06 17:30:57 -07:00
parent 93015236d9
commit 4b3687f9c1
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/rtc/rtc-pcap.c
View File

@ -151,6 +151,8 @@ static int __devinit pcap_rtc_probe(struct platform_device *pdev)
pcap_rtc->pcap = dev_get_drvdata(pdev->dev.parent); pcap_rtc->pcap = dev_get_drvdata(pdev->dev.parent);
platform_set_drvdata(pdev, pcap_rtc);
pcap_rtc->rtc = rtc_device_register("pcap", &pdev->dev, pcap_rtc->rtc = rtc_device_register("pcap", &pdev->dev,
&pcap_rtc_ops, THIS_MODULE); &pcap_rtc_ops, THIS_MODULE);
if (IS_ERR(pcap_rtc->rtc)) { if (IS_ERR(pcap_rtc->rtc)) {
@ -158,7 +160,6 @@ static int __devinit pcap_rtc_probe(struct platform_device *pdev)
goto fail_rtc; goto fail_rtc;
} }
platform_set_drvdata(pdev, pcap_rtc);
timer_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ); timer_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ);
alarm_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA); alarm_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA);
@ -177,6 +178,7 @@ fail_alarm:
fail_timer: fail_timer:
rtc_device_unregister(pcap_rtc->rtc); rtc_device_unregister(pcap_rtc->rtc);
fail_rtc: fail_rtc:
platform_set_drvdata(pdev, NULL);
kfree(pcap_rtc); kfree(pcap_rtc);
return err; return err;
} }