igb: fix a use-after-free issue in igb_clean_tx_ring

Fix the following use-after-free bug in igb_clean_tx_ring routine when
the NIC is running in XDP mode. The issue can be triggered redirecting
traffic into the igb NIC and then closing the device while the traffic
is flowing.

[   73.322719] CPU: 1 PID: 487 Comm: xdp_redirect Not tainted 5.18.3-apu2 #9
[   73.330639] Hardware name: PC Engines APU2/APU2, BIOS 4.0.7 02/28/2017
[   73.337434] RIP: 0010:refcount_warn_saturate+0xa7/0xf0
[   73.362283] RSP: 0018:ffffc9000081f798 EFLAGS: 00010282
[   73.367761] RAX: 0000000000000000 RBX: ffffc90000420f80 RCX: 0000000000000000
[   73.375200] RDX: ffff88811ad22d00 RSI: ffff88811ad171e0 RDI: ffff88811ad171e0
[   73.382590] RBP: 0000000000000900 R08: ffffffff82298f28 R09: 0000000000000058
[   73.390008] R10: 0000000000000219 R11: ffffffff82280f40 R12: 0000000000000090
[   73.397356] R13: ffff888102343a40 R14: ffff88810359e0e4 R15: 0000000000000000
[   73.404806] FS:  00007ff38d31d740(0000) GS:ffff88811ad00000(0000) knlGS:0000000000000000
[   73.413129] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   73.419096] CR2: 000055cff35f13f8 CR3: 0000000106391000 CR4: 00000000000406e0
[   73.426565] Call Trace:
[   73.429087]  <TASK>
[   73.431314]  igb_clean_tx_ring+0x43/0x140 [igb]
[   73.436002]  igb_down+0x1d7/0x220 [igb]
[   73.439974]  __igb_close+0x3c/0x120 [igb]
[   73.444118]  igb_xdp+0x10c/0x150 [igb]
[   73.447983]  ? igb_pci_sriov_configure+0x70/0x70 [igb]
[   73.453362]  dev_xdp_install+0xda/0x110
[   73.457371]  dev_xdp_attach+0x1da/0x550
[   73.461369]  do_setlink+0xfd0/0x10f0
[   73.465166]  ? __nla_validate_parse+0x89/0xc70
[   73.469714]  rtnl_setlink+0x11a/0x1e0
[   73.473547]  rtnetlink_rcv_msg+0x145/0x3d0
[   73.477709]  ? rtnl_calcit.isra.0+0x130/0x130
[   73.482258]  netlink_rcv_skb+0x8d/0x110
[   73.486229]  netlink_unicast+0x230/0x340
[   73.490317]  netlink_sendmsg+0x215/0x470
[   73.494395]  __sys_sendto+0x179/0x190
[   73.498268]  ? move_addr_to_user+0x37/0x70
[   73.502547]  ? __sys_getsockname+0x84/0xe0
[   73.506853]  ? netlink_setsockopt+0x1c1/0x4a0
[   73.511349]  ? __sys_setsockopt+0xc8/0x1d0
[   73.515636]  __x64_sys_sendto+0x20/0x30
[   73.519603]  do_syscall_64+0x3b/0x80
[   73.523399]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   73.528712] RIP: 0033:0x7ff38d41f20c
[   73.551866] RSP: 002b:00007fff3b945a68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[   73.559640] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff38d41f20c
[   73.567066] RDX: 0000000000000034 RSI: 00007fff3b945b30 RDI: 0000000000000003
[   73.574457] RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
[   73.581852] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff3b945ab0
[   73.589179] R13: 0000000000000000 R14: 0000000000000003 R15: 00007fff3b945b30
[   73.596545]  </TASK>
[   73.598842] ---[ end trace 0000000000000000 ]---

Fixes: 9cbc948b ("igb: add XDP support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/r/e5c01d549dc37bff18e46aeabd6fb28a7bcf84be.1655388571.git.lorenzo@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/intel/igb/igb_main.c

@@ -4819,8 +4819,11 @@ static void igb_clean_tx_ring(struct igb_ring *tx_ring)
 	while (i != tx_ring->next_to_use) {
 		union e1000_adv_tx_desc *eop_desc, *tx_desc;
 
-		/* Free all the Tx ring sk_buffs */
+		/* Free all the Tx ring sk_buffs or xdp frames */
+		if (tx_buffer->type == IGB_TYPE_SKB)
 			dev_kfree_skb_any(tx_buffer->skb);
+		else
+			xdp_return_frame(tx_buffer->xdpf);
 
 		/* unmap skb header data */
 		dma_unmap_single(tx_ring->dev,