igc: avoid kernel warning when changing RX ring parameters

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: igc: avoid kernel warning when changing RX ring parameters 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.

References

• https://git.kernel.org/stable/c/ab8c107470d12e7ef99030bf0911a10cdef62d16
• https://git.kernel.org/stable/c/3ddb49af08094ebee250b461172ee7b8e27a35d3
• https://git.kernel.org/stable/c/65aebcf1e05bd97d2e7ffcdff36efea1757c9450
• https://git.kernel.org/stable/c/453307b569a0d41bddd07f26bf41b784cd82a4c9