[tip:timers/urgent] rtc: Fix possible null pointer dereference in rtc-mpc5121.c

From: tip-bot for John Stultz
Date: Thu Apr 26 2012 - 05:23:16 EST


Commit-ID: e48b5e825f9c471cbcbfd934a4c2df27e9d39635
Gitweb: http://git.kernel.org/tip/e48b5e825f9c471cbcbfd934a4c2df27e9d39635
Author: John Stultz <john.stultz@xxxxxxxxxx>
AuthorDate: Tue, 24 Apr 2012 13:43:35 -0700
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 26 Apr 2012 11:17:01 +0200

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@xxxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1335300215-21427-1-git-send-email-john.stultz@xxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
drivers/rtc/rtc-mpc5121.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-mpc5121.c b/drivers/rtc/rtc-mpc5121.c
index 42f5f82..029e421 100644
--- 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;

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