From: Maxim Mikityanskiy maximmi@mellanox.com
[ Upstream commit b425e24a934e21a502d25089c6c7443d799c5594 ]
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 maximmi@mellanox.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Björn Töpel bjorn.topel@intel.com Link: https://lore.kernel.org/bpf/20210118160333.333439-1-maximmi@mellanox.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 d5f42c62fd79e..52fd1f96b241e 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -107,9 +107,9 @@ 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; }