From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martin KaFai Lau <kafai@fb.com>
Subject: Re: NULL pointer dereference in rt6_get_cookie()
Date: Mon, 12 Oct 2015 13:31:16 -0700
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References: <20151010132437.GB25926@orbit.nwl.cc>
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Cc: <netdev@vger.kernel.org>,
	Hannes Frederic Sowa <hannes@stressinduktion.org>,
	Steffen Klassert <steffen.klassert@secunet.com>,
	Julian Anastasov <ja@ssi.bg>
To: Phil Sutter <phil@nwl.cc>
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On Sat, Oct 10, 2015 at 03:24:37PM +0200, Phil Sutter wrote:
> Using printk-debugging I could track down the problem to
> rt6_get_cookie() function in include/net/ip6_fib.h:
>
> The conditional at the start of the function evaluates true, since
> 'rt->rt6i_flags & RTF_PCPU' is non-zero. Due to that, 'rt' pointer is
> reassigned:
>
> | rt = (struct rt6_info *)(rt->dst.from);
>
> It appears that this effectively assigns NULL to it, and the following
> dereference causes the bug.
Thanks for the report.  I am looking into it.

--Martin