This is a note to let you know that I've just added the patch titled net/mlx4_en: fixup xdp tx irq to match rx to the 4.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-mlx4_en-fixup-xdp-tx-irq-to-match-rx.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Nov 10 16:43:03 CET 2016 From: Brenden Blanco <bblanco@xxxxxxxxxxxx> Date: Thu, 13 Oct 2016 13:13:11 -0700 Subject: net/mlx4_en: fixup xdp tx irq to match rx From: Brenden Blanco <bblanco@xxxxxxxxxxxx> [ Upstream commit 958b3d396d7f80755e2c2e6a8f873a669f38de10 ] In cases where the number of tx rings is not a multiple of the number of rx rings, the tx completion event will be handled on a different core from the transmit and population of the ring. Races on the ring will lead to a double-free of the page, and possibly other corruption. The rings are initialized by default with a valid multiple of rings, based on the number of cpus, therefore an invalid configuration requires ethtool to change the ring layout. For instance 'ethtool -L eth0 rx 9 tx 8' will cause packets received on rx0, and XDP_TX'd to tx48, to be completed on cpu3 (48 % 9 == 3). Resolve this discrepancy by shifting the irq for the xdp tx queues to start again from 0, modulo rx_ring_num. Fixes: 9ecc2d86171a ("net/mlx4_en: add xdp forwarding and data write support") Reported-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> Signed-off-by: Brenden Blanco <bblanco@xxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/mellanox/mlx4/en_cq.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c @@ -127,7 +127,15 @@ int mlx4_en_activate_cq(struct mlx4_en_p /* For TX we use the same irq per ring we assigned for the RX */ struct mlx4_en_cq *rx_cq; + int xdp_index; + /* The xdp tx irq must align with the rx ring that forwards to + * it, so reindex these from 0. This should only happen when + * tx_ring_num is not a multiple of rx_ring_num. + */ + xdp_index = (priv->xdp_ring_num - priv->tx_ring_num) + cq_idx; + if (xdp_index >= 0) + cq_idx = xdp_index; cq_idx = cq_idx % priv->rx_ring_num; rx_cq = priv->rx_cq[cq_idx]; cq->vector = rx_cq->vector; Patches currently in stable-queue which might be from bblanco@xxxxxxxxxxxx are queue-4.8/net-mlx4_en-fixup-xdp-tx-irq-to-match-rx.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html