[PATCH 5.17 0522/1126] igc: avoid kernel warning when changing RX ring parameters

Greg Kroah-Hartman
2022-04-05T08:56:18Z

From: Corinna Vinschen <vinschen@redhat.com>

[ Upstream commit 453307b569a0d41bddd07f26bf41b784cd82a4c9 ]

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.

Fixes: 73f1071c1d29 ("igc: Add support for XDP_TX action")
Reported-by: Lennert Buytenhek <buytenh@arista.com>
Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/igc/igc_main.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 629e4a644a9d..2a9ae53238f7 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -505,6 +505,9 @@ int igc_setup_rx_resources(struct igc_ring *rx_ring)
u8 index = rx_ring->queue_index;
int size, desc_len, res;

+ /* 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) {
--
2.34.1