From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH v2] netlink: fix null pointer dereference on nlk->groups
Date: Sun, 10 Jan 2016 23:27:07 -0500 (EST)
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From: Baozeng Ding <sploving1@gmail.com>
Date: Sat,  9 Jan 2016 23:56:41 +0800

> If groups is not 0 and nlk->groups is NULL, it will not return
> immediately and cause a null pointer dereference later.
> 
> Signed-off-by: Baozeng Ding <sploving1@gmail.com>
> ---
> This version uses the preferred networking coding style. Thanks
> for Sergei's feedback. Also the patch keeps the original author's
> coding style as much as possible.

Is this an actual legal state?  If not, add a WARN_ON() check.

Otherwise, provide a proper OOPS log and explain how the state
can be achieved.

Thanks.