rtc: Fix possible null pointer dereference in rtc-mpc5121.c

Mark Loard pointed out:
"For example, this beauty from rtc-mpc5121.c in the same update:
   ...
   rtc->rtc = rtc_device_register("mpc5200-rtc", &op->dev,
                                   &mpc5200_rtc_ops, THIS_MODULE);
   ...

   rtc->rtc->uie_unsupported = 1;    // <<<< Ooops NULL pointer >>>>

   if (IS_ERR(rtc->rtc)) {           // <<<< this needs to be earlier >>>>
           err = PTR_ERR(rtc->rtc);
           goto out_free_irq;
   }
   ..."

This patch moves setting the uie_unsupported flag to after we validate
the rtc->rtc pointer to resolve this.

Reported by: Mark Lord <kernel@teksavvy.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1335300215-21427-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/drivers/rtc/rtc-mpc5121.c b/drivers/rtc/rtc-mpc5121.c
index 42f5f82..029e421 100644 (file)
--- a/drivers/rtc/rtc-mpc5121.c
+++ b/drivers/rtc/rtc-mpc5121.c
@@ -360,12 +360,11 @@ static int __devinit mpc5121_rtc_probe(struct platform_device *op)
                                                &mpc5200_rtc_ops, THIS_MODULE);
        }
 
-       rtc->rtc->uie_unsupported = 1;
-
        if (IS_ERR(rtc->rtc)) {
                err = PTR_ERR(rtc->rtc);
                goto out_free_irq;
        }
+       rtc->rtc->uie_unsupported = 1;
 
        return 0;