From: Tong Zhu <zhutong@amazon.com>
To: <davem@davemloft.net>, <sashal@kernel.org>, <edumazet@google.com>,
<zhutong@amazon.com>, <vvs@virtuozzo.com>
Cc: <netdev@vger.kernel.org>, <stable@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH] neighbour: Disregard DEAD dst in neigh_update
Date: Wed, 30 Dec 2020 17:54:23 -0500 [thread overview]
Message-ID: <20201230225415.GA490@ucf43ac461c9a53.ant.amazon.com> (raw)
In 4.x kernel a dst in DST_OBSOLETE_DEAD state is associated
with loopback net_device and leads to loopback neighbour. It
leads to an ethernet header with all zero addresses.
A very troubling case is working with mac80211 and ath9k.
A packet with all zero source MAC address to mac80211 will
eventually fail ieee80211_find_sta_by_ifaddr in ath9k (xmit.c).
As result, ath9k flushes tx queue (ath_tx_complete_aggr) without
updating baw (block ack window), damages baw logic and disables
transmission.
Signed-off-by: Tong Zhu <zhutong@amazon.com>
---
net/core/neighbour.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 6e890f51b7d8..e471c32e448f 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1271,7 +1271,7 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
* we can reinject the packet there.
*/
n2 = NULL;
- if (dst) {
+ if (dst && dst->obsolete != DST_OBSOLETE_DEAD) {
n2 = dst_neigh_lookup_skb(dst, skb);
if (n2)
n1 = n2;
--
2.17.1
next reply other threads:[~2020-12-30 22:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-30 22:54 Tong Zhu [this message]
2021-01-06 0:05 ` [PATCH] neighbour: Disregard DEAD dst in neigh_update David Miller
2021-01-08 2:36 ` Your Real Name
2021-01-08 7:34 ` Greg KH
2021-03-19 18:33 Tong Zhu
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