diff options
| author | Bryam Vargas <hexlabsecurity@proton.me> | 2026-06-25 04:51:20 -0500 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-06-26 18:52:26 -0700 |
| commit | 54f6b0c843e228d499eb4b6bbb89df68cad9ad5d (patch) | |
| tree | 2627563bffb06bc2527cf82e32d4723884973329 /net | |
| parent | e056e1dfcddca877dd46d704e8ec9860cfc9ec44 (diff) | |
| download | linux-54f6b0c843e228d499eb4b6bbb89df68cad9ad5d.tar.gz linux-54f6b0c843e228d499eb4b6bbb89df68cad9ad5d.zip | |
net/sched: sch_multiq: Replace direct dequeue call with peek and qdisc_dequeue_peeked
multiq_dequeue() takes a packet from a band's child with a direct
->dequeue() call after multiq_peek() peeked it. When the child is
non-work-conserving the peek stashes the skb in the child's gso_skb, so
the direct dequeue returns a different skb and orphans the stash,
desyncing the child's qlen/backlog. With a qfq child reached through a
peeking parent (e.g. tbf) this re-enters the child on an emptied list and
dereferences NULL, panicking the kernel from softirq on ordinary egress.
Take the packet through qdisc_dequeue_peeked(), as sch_prio already does
and as sch_red and sch_sfb were just fixed to do. The helper is a no-op
when the child has no stash, so a work-conserving child is unaffected.
Fixes: 77be155cba4e ("pkt_sched: Add peek emulation for non-work-conserving qdiscs.")
Cc: stable@vger.kernel.org
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20260625-b4-disp-31bcb279-v1-2-85c40b83c529@proton.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sched/sch_multiq.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c index 4e465d11e3d7..a467dd122369 100644 --- a/net/sched/sch_multiq.c +++ b/net/sched/sch_multiq.c @@ -103,7 +103,7 @@ static struct sk_buff *multiq_dequeue(struct Qdisc *sch) if (!netif_xmit_stopped( netdev_get_tx_queue(qdisc_dev(sch), q->curband))) { qdisc = q->queues[q->curband]; - skb = qdisc->dequeue(qdisc); + skb = qdisc_dequeue_peeked(qdisc); if (skb) { qdisc_bstats_update(sch, skb); qdisc_qlen_dec(sch); |