[Intel-wired-lan] [PATCH 1/2 net-next v4] igc: avoid kernel warning when changing RX ring parameters
Lennert Buytenhek
buytenh at wantstofly.org
Mon Jan 17 14:57:36 UTC 2022
On Fri, Jan 14, 2022 at 08:45:19PM +0100, Corinna Vinschen wrote:
> Calling ethtool changing the RX ring parameters like this:
>
> $ ethtool -G eth0 rx 1024
>
> on igc triggers kernel warnings like this:
>
> [ 225.198467] ------------[ cut here ]------------
> [ 225.198473] Missing unregister, handled but fix driver
> [ 225.198485] WARNING: CPU: 7 PID: 959 at net/core/xdp.c:168
> xdp_rxq_info_reg+0x79/0xd0
> [...]
> [ 225.198601] Call Trace:
> [ 225.198604] <TASK>
> [ 225.198609] igc_setup_rx_resources+0x3f/0xe0 [igc]
> [ 225.198617] igc_ethtool_set_ringparam+0x30e/0x450 [igc]
> [ 225.198626] ethnl_set_rings+0x18a/0x250
> [ 225.198631] genl_family_rcv_msg_doit+0xca/0x110
> [ 225.198637] genl_rcv_msg+0xce/0x1c0
> [ 225.198640] ? rings_prepare_data+0x60/0x60
> [ 225.198644] ? genl_get_cmd+0xd0/0xd0
> [ 225.198647] netlink_rcv_skb+0x4e/0xf0
> [ 225.198652] genl_rcv+0x24/0x40
> [ 225.198655] netlink_unicast+0x20e/0x330
> [ 225.198659] netlink_sendmsg+0x23f/0x480
> [ 225.198663] sock_sendmsg+0x5b/0x60
> [ 225.198667] __sys_sendto+0xf0/0x160
> [ 225.198671] ? handle_mm_fault+0xb2/0x280
> [ 225.198676] ? do_user_addr_fault+0x1eb/0x690
> [ 225.198680] __x64_sys_sendto+0x20/0x30
> [ 225.198683] do_syscall_64+0x38/0x90
> [ 225.198687] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 225.198693] RIP: 0033:0x7f7ae38ac3aa
>
> igc_ethtool_set_ringparam() copies the igc_ring structure but neglects to
> reset the xdp_rxq_info member before calling igc_setup_rx_resources().
> This in turn calls xdp_rxq_info_reg() with an already registered xdp_rxq_info.
>
> Make sure to unregister the xdp_rxq_info structure first in
> igc_setup_rx_resources. Move xdp_rxq_info handling down to be the last
> action, thus allowing to remove the xdp_rxq_info_unreg call in the error path.
>
> Fixes: 73f1071c1d29 ("igc: Add support for XDP_TX action")
> Reported-by: Lennert Buytenhek <buytenh at arista.com>
> Signed-off-by: Corinna Vinschen <vinschen at redhat.com>
> ---
> drivers/net/ethernet/intel/igc/igc_main.c | 20 +++++++++++---------
> 1 file changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
> index 2f17f36e94fd..56ed0f1463e5 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -505,14 +505,6 @@ int igc_setup_rx_resources(struct igc_ring *rx_ring)
> u8 index = rx_ring->queue_index;
> int size, desc_len, res;
>
> - res = xdp_rxq_info_reg(&rx_ring->xdp_rxq, ndev, index,
> - rx_ring->q_vector->napi.napi_id);
> - if (res < 0) {
> - netdev_err(ndev, "Failed to register xdp_rxq index %u\n",
> - index);
> - return res;
> - }
> -
> size = sizeof(struct igc_rx_buffer) * rx_ring->count;
> rx_ring->rx_buffer_info = vzalloc(size);
> if (!rx_ring->rx_buffer_info)
> @@ -534,10 +526,20 @@ int igc_setup_rx_resources(struct igc_ring *rx_ring)
> rx_ring->next_to_clean = 0;
> rx_ring->next_to_use = 0;
>
> + /* XDP RX-queue info */
> + if (xdp_rxq_info_is_reg(&rx_ring->xdp_rxq))
> + xdp_rxq_info_unreg(&rx_ring->xdp_rxq);
> + res = xdp_rxq_info_reg(&rx_ring->xdp_rxq, ndev, index,
> + rx_ring->q_vector->napi.napi_id);
> + if (res < 0) {
> + netdev_err(ndev, "Failed to register xdp_rxq index %u\n",
> + index);
> + goto err;
> + }
> +
> return 0;
>
> err:
> - xdp_rxq_info_unreg(&rx_ring->xdp_rxq);
> vfree(rx_ring->rx_buffer_info);
> rx_ring->rx_buffer_info = NULL;
> netdev_err(ndev, "Unable to allocate memory for Rx descriptor ring\n");
This patch fixes the warning...
Tested-by: Lennert Buytenhek <buytenh at arista.com>
...but doesn't it now forget to free rx_ring->desc if xdp_rxq_info_reg()
fails?
Thank you!
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