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author | Tong Zhu <zhutong@amazon.com> | 2021-03-19 19:33:37 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2021-03-31 23:10:46 +0200 |
commit | d47ec7a0a7271dda08932d6208e4ab65ab0c987c (patch) | |
tree | 77f87ea9b8f9e7ab159cbebb9633f9e22816a90d /net/rds | |
parent | net: ensure mac header is set in virtio_net_hdr_to_skb() (diff) | |
download | linux-d47ec7a0a7271dda08932d6208e4ab65ab0c987c.tar.xz linux-d47ec7a0a7271dda08932d6208e4ab65ab0c987c.zip |
neighbour: Disregard DEAD dst in neigh_update
After a short network outage, the dst_entry is timed out and put
in DST_OBSOLETE_DEAD. We are in this code because arp reply comes
from this neighbour after network recovers. There is a potential
race condition that dst_entry is still in DST_OBSOLETE_DEAD.
With that, another neighbour lookup causes more harm than good.
In best case all packets in arp_queue are lost. This is
counterproductive to the original goal of finding a better path
for those packets.
I observed a worst case with 4.x kernel where a dst_entry in
DST_OBSOLETE_DEAD state is associated with loopback net_device.
It leads to an ethernet header with all zero addresses.
A packet with all zero source MAC address is quite deadly with
mac80211, ath9k and 802.11 block ack. It fails
ieee80211_find_sta_by_ifaddr in ath9k (xmit.c). Ath9k flushes tx
queue (ath_tx_complete_aggr). BAW (block ack window) is not
updated. BAW logic is damaged and ath9k transmission is disabled.
Signed-off-by: Tong Zhu <zhutong@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rds')
0 files changed, 0 insertions, 0 deletions