[Bridge] [PATCH] net bridge: add null pointer check, fix panic

[Eric Dumazet]

On Thu, 2013-06-20 at 15:47 +0800, xiaoming gao wrote:

> 
> if you remove the test on FF_BRIDGE_PORT, and br_port_get_rcu never returns NULL, the problem is fixed.
> but the codes in mainline is still bugged, am i right??
> by the way, kernel-stable 3.0 and 3.4 tree also have this bug, and is very easily to reproduce.

Commit 00cfec37484761a4 has to be backported anyway, if not already
backported.

I would rather fix things properly, instead of adding defensive code.