tree 5b4432cdf877af3ad989eb12c1d63f481dc89a8b
parent 0ed4229b08c13c84a3c301a08defdc9e7f4467e6
author Li RongQing <lirongqing@baidu.com> 1533282321 +0800
committer David S. Miller <davem@davemloft.net> 1533515085 -0700

net: check extack._msg before print

dev_set_mtu_ext is able to fail with a valid mtu value, at that
condition, extack._msg is not set and random since it is in stack,
then kernel will crash when print it.

Fixes: 7a4c53bee3324a ("net: report invalid mtu value via netlink extack")
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>