From b7454f1940c5e6d92e753853c476a769e452f30a Mon Sep 17 00:00:00 2001 From: Weiming Shi Date: Fri, 2 Oct 2026 02:23:25 +0800 Subject: [PATCH 1/2] net: team: stop reusing skb after queue override A nonzero dev_queue_xmit() result does not return ownership of the skb. When an override port's qdisc drops it, the queue override helper used to try another port or the mode transmit op with the freed skb. Return the handoff decision separately from transmit success. Select only the first override port under RCU and stop after handing it the skb, regardless of the lower transmit result. Keep the existing success and drop accounting. BUG: KASAN: slab-use-after-free in sk_skb_reason_drop Write of size 4 by task poc/5040 sk_skb_reason_drop (net/core/skbuff.c:1240) dev_kfree_skb_any_reason (net/core/dev.c:3470) ab_transmit (drivers/net/team/team_mode_activebackup.c:49) team_xmit (drivers/net/team/team_core.c:1849) __dev_direct_xmit (net/core/dev.c:4934) Freed by task 5040: __tcf_kfree_skb_list (net/sched/sch_generic.c:43) __dev_queue_xmit (net/core/dev.c:4831) team_xmit (drivers/net/team/team_core.c:1846) Kernel panic - not syncing: KASAN: panic_on_warn set ... Cc: stable@vger.kernel.org Fixes: 8ff5105a2b9d ("team: add support for queue override by setting queue_id for port") Reported-by: Signed-off-by: Weiming Shi Link: https://patch.msgid.link/20261001182326.572045-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/team/team_core.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c index beffbe450612..ca75f08e3c59 100644 --- a/drivers/net/team/team_core.c +++ b/drivers/net/team/team_core.c @@ -820,7 +820,8 @@ static struct list_head *__team_get_qom_list(struct team *team, u16 queue_id) /* * note: already called with rcu_read_lock */ -static bool team_queue_override_transmit(struct team *team, struct sk_buff *skb) +static bool team_queue_override_transmit(struct team *team, struct sk_buff *skb, + bool *tx_success) { struct list_head *qom_list; struct team_port *port; @@ -828,11 +829,11 @@ static bool team_queue_override_transmit(struct team *team, struct sk_buff *skb) if (!team->queue_override_enabled || !skb->queue_mapping) return false; qom_list = __team_get_qom_list(team, skb->queue_mapping); - list_for_each_entry_rcu(port, qom_list, qom_list) { - if (!team_dev_queue_xmit(team, port, skb)) - return true; - } - return false; + port = list_first_or_null_rcu(qom_list, struct team_port, qom_list); + if (!port) + return false; + *tx_success = !team_dev_queue_xmit(team, port, skb); + return true; } static void __team_queue_override_port_del(struct team *team, @@ -1864,8 +1865,7 @@ static netdev_tx_t team_xmit(struct sk_buff *skb, struct net_device *dev) bool tx_success; unsigned int len = skb->len; - tx_success = team_queue_override_transmit(team, skb); - if (!tx_success) + if (!team_queue_override_transmit(team, skb, &tx_success)) tx_success = READ_ONCE(team->ops.transmit)(team, skb); if (tx_success) { struct team_pcpu_stats *pcpu_stats; From 489114c9ecae44e523361a4b3e610ee5ebd9189c Mon Sep 17 00:00:00 2001 From: Weiming Shi Date: Fri, 2 Oct 2026 02:23:26 +0800 Subject: [PATCH 2/2] net: team: free skb when broadcast has no txable port bc_transmit() sends the original skb through the last txable port. When no port is txable, it returns false without consuming the skb, but team_xmit() still returns NETDEV_TX_OK. AF_PACKET sends then retain the skb and its socket write-memory charge. A TX-enabled, link-down port keeps the broadcast transmit op installed. Carrier can stay up through a second link-up, TX-disabled port or be forced on by userspace. Free the original skb on the no-port path while leaving the existing drop accounting intact. Discovered by Sashiko during review of previous commit. Cc: stable@vger.kernel.org Fixes: 5fc889911a99 ("team: add broadcast mode") Signed-off-by: Weiming Shi Link: https://patch.msgid.link/20261001182326.572045-3-bestswngs@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/team/team_mode_broadcast.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/team/team_mode_broadcast.c b/drivers/net/team/team_mode_broadcast.c index 61d7d79f0c36..69dc25a5847a 100644 --- a/drivers/net/team/team_mode_broadcast.c +++ b/drivers/net/team/team_mode_broadcast.c @@ -37,6 +37,8 @@ static bool bc_transmit(struct team *team, struct sk_buff *skb) ret = !team_dev_queue_xmit(team, last, skb); if (!sum_ret) sum_ret = ret; + } else { + dev_kfree_skb_any(skb); } return sum_ret; }