[098/200] rtc-cmos: do dev_set_drvdata() earlier in the initialization

[Greg KH]

2.6.34-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <error27@xxxxxxxxx>

commit 6ba8bcd457d9fc793ac9435aa2e4138f571d4ec5 upstream.

The bug is an oops when dev_get_drvdata() returned null in
cmos_update_irq_enable().  The call tree looks like this:
  rtc_dev_ioctl()
    => rtc_update_irq_enable()
      => cmos_update_irq_enable()

It's caused by a race condition in the module initialization.  It is
rtc_device_register() which makes the ioctl operations live so I moved
the call to dev_set_drvdata() before the call to rtc_device_register().

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=15963

Reported-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
Tested-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Cc: Paul Gortmaker <p_gortmaker@xxxxxxxxx>
Cc: Malte Schroder <maltesch@xxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Herton Ronaldo Krzesinski <herton@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/rtc/rtc-cmos.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -719,6 +719,9 @@ cmos_do_probe(struct device *dev, struct
 		}
 	}
 
+	cmos_rtc.dev = dev;
+	dev_set_drvdata(dev, &cmos_rtc);
+
 	cmos_rtc.rtc = rtc_device_register(driver_name, dev,
 				&cmos_rtc_ops, THIS_MODULE);
 	if (IS_ERR(cmos_rtc.rtc)) {
@@ -726,8 +729,6 @@ cmos_do_probe(struct device *dev, struct
 		goto cleanup0;
 	}
 
-	cmos_rtc.dev = dev;
-	dev_set_drvdata(dev, &cmos_rtc);
 	rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 
 	spin_lock_irq(&rtc_lock);


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