From: Nikolay Aleksandrov <redacted>
Date: Tue,  6 Jun 2017 01:26:24 +0300

We might call br_afspec() with p == NULL which is a valid use case if
the action is on the bridge device itself, but the bridge tunnel code
dereferences the p pointer without checking, so check if p is null
first.

Reported-by: Gustavo A. R. Silva <redacted>
Fixes: efa5356b0d97 ("bridge: per vlan dst_metadata netlink support")
Signed-off-by: Nikolay Aleksandrov <redacted>

Applied and queued up for -stable, thanks Nikolay.