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Date: Sun, 19 Jul 2009 17:12:58 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Dan Carpenter <error27@gmail.com>
cc: LKML <linux-kernel@vger.kernel.org>, John Stultz <johnstul@us.ibm.com>
Subject: Re: potential null dereference in sysfs_override_clocksource()
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Dan,

On Sun, 19 Jul 2009, Dan Carpenter wrote:

> Hello,
> 
> I am testing a source checker (http://repo.or.cz/w/smatch.git).
> 
> It found an issue in sysfs_override_clocksource() from 
> kernel/time/clocksource.c.  If "len" is zero then "ovr" is null and 
> checking ovr->flags will oops on line 517.
> 
> kernel/time/clocksource.c
>    516          if (tick_oneshot_mode_active() &&
>    517              !(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) {
>    518                  printk(KERN_WARNING "%s clocksource is not HRT compatible. "

Indeed. I queued a fix.

Thanks for pointing it out,


       tglx