USB ethernet devices stop responding when plugged in to USB3 XHCI ports and flooded with incoming traffic. The usbnet layer seems to get -EPROTO from the xhci driver. Nothing is usually logged in kernel when this occurs, but with dyndebug on there are errors like: ax88179_178a 4-1.1:1.0 eth0: tx throttle -71 intr status -71 Sometimes: xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called with disabled ep ffff88024ea1adc8 To reproduce just flood the adaptor with gigabit traffic from another computer for a couple of minutes with any of: ping -f $host iperf3 -c $host -t 1000 -P 128 iperf3 -c $host -u -b $bandwidth (for iperf tests run 'iperf3 -s' on the test platform) iperf3 shows many errors/retries. If slub_debug is on (specifically slub_debug=U) there are more retries and it fails faster, which suggests some kind of memory corruption. Other slub_debug options do not appear to have any effect. Another symptom of memory corruption is that other USB devices plugged in to different ports will disconnect and reconnect. The problem is not these devices though, as the USB ethernet still fails when all other devices are unplugged. I have reproduced this with an AX88179 USB3 gigabit ethernet adaptor and a dm9601 USB1 10/100 adaptor, on both a laptop with Intel XHCI chipset and a desktop with VIA XHCI chipset. With the dm9601 adaptor just running "iperf3 -c z -t 10 -u -b 12m" (12mbit UDP stream) is enough to quickly kill it. I have verified that the bug does not occur with USB2 chipset of the desktop, only USB3. This bug appears to have been around a long time. There are some relevant bug threads, several refer specifically to disconnects on flooding with AX88179: http://www.spinics.net/lists/linux-usb/msg113358.html https://bugzilla.kernel.org/show_bug.cgi?id=75381 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1371233 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1269883 I bisected this with the AX88179 but it just led back to v3.11-rc1-224-g452c447a497d ("USBNET: increase max rx/tx qlen for improving USB3 thoughtput") which is probably not the actual cause of the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
