net/sched: act_mirred: Add carrier check

[ Upstream commit 526f28bd0fbdc699cda31426928802650c1528e5 ]

There are cases where the device is adminstratively UP, but operationally
down. For example, we have a physical device (Nvidia ConnectX-6 Dx, 25Gbps)
who's cable was pulled out, here is its ip link output:

5: ens2f1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
    link/ether b8:ce:f6:4b:68:35 brd ff:ff:ff:ff:ff:ff
    altname enp179s0f1np1

As you can see, it's administratively UP but operationally down.
In this case, sending a packet to this port caused a nasty kernel hang (so
nasty that we were unable to capture it). Aborting a transmit based on
operational status (in addition to administrative status) fixes the issue.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
v1->v2: Add fixes tag
v2->v3: Remove blank line between tags + add change log, suggested by Leon
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index baeae5e..36395e5 100644 (file)
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -262,7 +262,7 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
                goto out;
        }
 
-       if (unlikely(!(dev->flags & IFF_UP))) {
+       if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) {
                net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
                                       dev->name);
                goto out;