diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-06-06 16:51:27 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-19 15:32:28 +0200 |
| commit | d1bc80da75c789f2f6830df89d91fb2f7a509943 (patch) | |
| tree | d76b13bd01c4c623bf5764c5b9a1ba374a87e7c6 | |
| parent | 98e46d77cd8be70eb191ffc2e6bc99fe13db766b (diff) | |
net_sched: sch_sfq: fix a potential crash on gso_skb handling
[ Upstream commit 82ffbe7776d0ac084031f114167712269bf3d832 ]
SFQ has an assumption of always being able to queue at least one packet.
However, after the blamed commit, sch->q.len can be inflated by packets
in sch->gso_skb, and an enqueue() on an empty SFQ qdisc can be followed
by an immediate drop.
Fix sfq_drop() to properly clear q->tail in this situation.
Tested:
ip netns add lb
ip link add dev to-lb type veth peer name in-lb netns lb
ethtool -K to-lb tso off # force qdisc to requeue gso_skb
ip netns exec lb ethtool -K in-lb gro on # enable NAPI
ip link set dev to-lb up
ip -netns lb link set dev in-lb up
ip addr add dev to-lb 192.168.20.1/24
ip -netns lb addr add dev in-lb 192.168.20.2/24
tc qdisc replace dev to-lb root sfq limit 100
ip netns exec lb netserver
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
Fixes: a53851e2c321 ("net: sched: explicit locking in gso_cpu fallback")
Reported-by: Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de>
Closes: https://lore.kernel.org/netdev/9da42688-bfaa-4364-8797-e9271f3bdaef@hetzner-cloud.de/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250606165127.3629486-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/sched/sch_sfq.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c index 58b42dcf8f20..a903b3c46805 100644 --- a/net/sched/sch_sfq.c +++ b/net/sched/sch_sfq.c @@ -310,7 +310,10 @@ drop: /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */ x = q->tail->next; slot = &q->slots[x]; - q->tail->next = slot->next; + if (slot->next == x) + q->tail = NULL; /* no more active slots */ + else + q->tail->next = slot->next; q->ht[slot->hash] = SFQ_EMPTY_SLOT; goto drop; } |