From b425e24a934e21a502d25089c6c7443d799c5594 Mon Sep 17 00:00:00 2001 From: Maxim Mikityanskiy Date: Mon, 18 Jan 2021 18:03:33 +0200 Subject: [PATCH] xsk: Clear pool even for inactive queues MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The number of queues can change by other means, rather than ethtool. For example, attaching an mqprio qdisc with num_tc > 1 leads to creating multiple sets of TX queues, which may be then destroyed when mqprio is deleted. If an AF_XDP socket is created while mqprio is active, dev->_tx[queue_id].pool will be filled, but then real_num_tx_queues may decrease with deletion of mqprio, which will mean that the pool won't be NULLed, and a further increase of the number of TX queues may expose a dangling pointer. To avoid any potential misbehavior, this commit clears pool for RX and TX queues, regardless of real_num_*_queues, still taking into consideration num_*_queues to avoid overflows. Fixes: 1c1efc2af158 ("xsk: Create and free buffer pool independently from umem") Fixes: a41b4f3c58dd ("xsk: simplify xdp_clear_umem_at_qid implementation") Signed-off-by: Maxim Mikityanskiy Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20210118160333.333439-1-maximmi@mellanox.com --- net/xdp/xsk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 8037b04..4a83117 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -108,9 +108,9 @@ EXPORT_SYMBOL(xsk_get_pool_from_qid); void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id) { - if (queue_id < dev->real_num_rx_queues) + if (queue_id < dev->num_rx_queues) dev->_rx[queue_id].pool = NULL; - if (queue_id < dev->real_num_tx_queues) + if (queue_id < dev->num_tx_queues) dev->_tx[queue_id].pool = NULL; } -- 2.7.4