linux/drivers/net
Alexander Kappner bb1b40c7cb usbnet: ipheth: prevent TX queue timeouts when device not ready
iOS devices require the host to be "trusted" before servicing network
packets. Establishing trust requires the user to confirm a dialog on the
iOS device.Until trust is established, the iOS device will silently discard
network packets from the host. Currently, the ipheth driver does not detect
whether an iOS device has established trust with the host, and immediately
sets up the transmit queues.

This causes the following problems:

- Kernel taint due to WARN() in netdev watchdog.
- Dmesg spam ("TX timeout").
- Disruption of user space networking activity (dhcpd, etc...) when new
interface comes up but cannot be used.
- Unnecessary host and device wakeups and USB traffic

Example dmesg output:

[ 1101.319778] NETDEV WATCHDOG: eth1 (ipheth): transmit queue 0 timed out
[ 1101.319817] ------------[ cut here ]------------
[ 1101.319828] WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:316 dev_watchdog+0x20f/0x220
[ 1101.319831] Modules linked in: ipheth usbmon nvidia_drm(PO) nvidia_modeset(PO) nvidia(PO) iwlmvm mac80211 iwlwifi btusb btrtl btbcm btintel qmi_wwan bluetooth cfg80211 ecdh_generic thinkpad_acpi rfkill [last unloaded: ipheth]
[ 1101.319861] CPU: 0 PID: 0 Comm: swapper/0 Tainted: P           O    4.13.12.1 #1
[ 1101.319864] Hardware name: LENOVO 20ENCTO1WW/20ENCTO1WW, BIOS N1EET62W (1.35 ) 11/10/2016
[ 1101.319867] task: ffffffff81e11500 task.stack: ffffffff81e00000
[ 1101.319873] RIP: 0010:dev_watchdog+0x20f/0x220
[ 1101.319876] RSP: 0018:ffff8810a3c03e98 EFLAGS: 00010292
[ 1101.319880] RAX: 000000000000003a RBX: 0000000000000000 RCX: 0000000000000000
[ 1101.319883] RDX: ffff8810a3c15c48 RSI: ffffffff81ccbfc2 RDI: 00000000ffffffff
[ 1101.319886] RBP: ffff880c04ebc41c R08: 0000000000000000 R09: 0000000000000379
[ 1101.319889] R10: 00000100696589d0 R11: 0000000000000378 R12: ffff880c04ebc000
[ 1101.319892] R13: 0000000000000000 R14: 0000000000000001 R15: ffff880c2865fc80
[ 1101.319896] FS:  0000000000000000(0000) GS:ffff8810a3c00000(0000) knlGS:0000000000000000
[ 1101.319899] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1101.319902] CR2: 00007f3ff24ac000 CR3: 0000000001e0a000 CR4: 00000000003406f0
[ 1101.319905] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1101.319908] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1101.319910] Call Trace:
[ 1101.319914]  <IRQ>
[ 1101.319921]  ? dev_graft_qdisc+0x70/0x70
[ 1101.319928]  ? dev_graft_qdisc+0x70/0x70
[ 1101.319934]  ? call_timer_fn+0x2e/0x170
[ 1101.319939]  ? dev_graft_qdisc+0x70/0x70
[ 1101.319944]  ? run_timer_softirq+0x1ea/0x440
[ 1101.319951]  ? timerqueue_add+0x54/0x80
[ 1101.319956]  ? enqueue_hrtimer+0x38/0xa0
[ 1101.319963]  ? __do_softirq+0xed/0x2e7
[ 1101.319970]  ? irq_exit+0xb4/0xc0
[ 1101.319976]  ? smp_apic_timer_interrupt+0x39/0x50
[ 1101.319981]  ? apic_timer_interrupt+0x8c/0xa0
[ 1101.319983]  </IRQ>
[ 1101.319992]  ? cpuidle_enter_state+0xfa/0x2a0
[ 1101.319999]  ? do_idle+0x1a3/0x1f0
[ 1101.320004]  ? cpu_startup_entry+0x5f/0x70
[ 1101.320011]  ? start_kernel+0x444/0x44c
[ 1101.320017]  ? early_idt_handler_array+0x120/0x120
[ 1101.320023]  ? x86_64_start_kernel+0x145/0x154
[ 1101.320028]  ? secondary_startup_64+0x9f/0x9f
[ 1101.320033] Code: 20 04 00 00 eb 9f 4c 89 e7 c6 05 59 44 71 00 01 e8 a7 df fd ff 89 d9 4c 89 e6 48 c7 c7 70 b7 cd 81 48 89 c2 31 c0 e8 97 64 90 ff <0f> ff eb bf 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00
[ 1101.320103] ---[ end trace 0cc4d251e2b57080 ]---
[ 1101.320110] ipheth 1-5:4.2: ipheth_tx_timeout: TX timeout

The last message "TX timeout" is repeated every 5 seconds until trust is
established or the device is disconnected, filling up dmesg.

The proposed patch eliminates the problem by, upon connection, keeping the
TX queue and carrier disabled until a packet is first received from the iOS
device. This is reflected by the confirmed_pairing variable in the device
structure. Only after at least one packet has been received from the iOS
device, the transmit queue and carrier are brought up during the periodic
device poll in ipheth_carrier_set. Because the iOS device will always send
a packet immediately upon trust being established, this should not delay
the interface becoming useable. To prevent failed UBRs in
ipheth_rcvbulk_callback from perpetually re-enabling the queue if it was
disabled, a new check is added so only successful transfers re-enable the
queue, whereas failed transfers only trigger an immediate poll.

This has the added benefit of removing the periodic control requests to the
iOS device until trust has been established and thus should reduce wakeup
events on both the host and the iOS device.

Signed-off-by: Alexander Kappner <agk@godking.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-15 13:51:46 +09:00
..
appletalk Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
arcnet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
bonding Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-10 10:00:18 +09:00
caif Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
can Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-12 09:17:05 +09:00
cris License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dsa net: dsa: lan9303: correctly check return value of devm_gpiod_get_optional 2017-11-14 21:34:57 +09:00
ethernet net: stmmac: fix LPI transitioning for dwmac4 2017-11-14 22:04:56 +09:00
fddi License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fjes
hamradio Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
hippi Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
hyperv hv_netvsc: hide warnings about uninitialized/missing rndis device 2017-11-08 10:28:54 +09:00
ieee802154 ieee802154: ca8210: use __func__ macro for debug messages 2017-11-06 16:39:14 +01:00
ipvlan ipvlan: fix ipv6 outbound device 2017-11-11 19:27:05 +09:00
phy net: phy: realtek: fix RTL8211F interrupt mode 2017-11-14 21:33:50 +09:00
plip net: plip: mark expected switch fall-throughs 2017-11-05 22:19:00 +09:00
ppp ppp: exit_net cleanup checks added 2017-11-14 15:46:17 +09:00
slip Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
team Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
usb usbnet: ipheth: prevent TX queue timeouts when device not ready 2017-11-15 13:51:46 +09:00
vmxnet3
wan net: wan: x25_asy: mark expected switch fall-through 2017-11-11 19:10:06 +09:00
wimax License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
wireless brcmfmac: add CLM download support 2017-11-11 03:04:09 +02:00
xen-netback Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-22 13:39:14 +01:00
dummy.c net: remove MTU limits for dummy and ifb device 2017-09-25 16:26:09 -07:00
eql.c
geneve.c geneve: exit_net cleanup check added 2017-11-14 15:45:52 +09:00
gtp.c
ifb.c net: remove MTU limits for dummy and ifb device 2017-09-25 16:26:09 -07:00
Kconfig net: Add support for networking over Thunderbolt cable 2017-10-02 11:24:42 -07:00
LICENSE.SRC
loopback.c
macsec.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-22 13:39:14 +01:00
macvlan.c macvlan/macvtap: Add support for L2 forwarding offloads with macvtap 2017-10-19 12:43:59 +01:00
macvtap.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-10-30 21:09:24 +09:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
mdio.c
mii.c
netconsole.c
nlmon.c
ntb_netdev.c drivers/net: ntb_netdev: Convert timers to use timer_setup() 2017-11-01 12:38:45 +09:00
rionet.c
sb1000.c
Space.c
sungem_phy.c
tap.c tun/tap: sanitize TUNSETSNDBUF input 2017-11-01 20:52:36 +09:00
thunderbolt.c net: thunderbolt: Clear finished Tx frame bus address in tbnet_tx_callback() 2017-11-11 19:20:45 +09:00
tun.c net: bpf: rename ndo_xdp to ndo_bpf 2017-11-05 22:26:18 +09:00
veth.c
virtio_net.
virtio_net.c net: bpf: rename ndo_xdp to ndo_bpf 2017-11-05 22:26:18 +09:00
vrf.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
vsockmon.c
vxlan.c vxlan: fix the issue that neigh proxy blocks all icmpv6 packets 2017-11-14 16:12:01 +09:00
xen-netfront.c xen-netfront, xen-netback: Use correct minimum MTU values 2017-10-16 16:00:44 -04:00