Comment 1 by Andreas Kemnade, Feb 16, 2019

seen also on 4.17.10:
here is the log surrounding it.

[  561.189544] net hso0: Invalid frame (0) length
[  709.656402] net hso0: Invalid frame (0) length
[  996.427001] net hso0: Invalid frame (0) length
[ 1068.243988] usb usb2-port2: disabled by hub (EMI?), 
re-enabling...
[ 1068.258392] usb 2-2: USB disconnect, device number 2
[ 1716.342193] systemd-logind[3122]: New session 4 of user root.
[ 1732.828430] ehci-omap 48064800.ehci: remove, state 4
[ 1732.860748] usb usb2: USB disconnect, device number 1
[ 1732.872070] ehci-omap 48064800.ehci: USB bus 2 deregistered
[ 1736.124725] ehci-omap: OMAP-EHCI Host Controller driver
[ 1736.231628] ehci-omap 48064800.ehci: EHCI Host Controller
[ 1736.246063] ehci-omap 48064800.ehci: new USB bus registered, 
assigned bus number 2
[ 1736.255554] ehci-omap 48064800.ehci: irq 93, io mem 0x48064800
[ 1736.291137] ehci-omap 48064800.ehci: USB 2.0 started, EHCI 1.00
[ 1736.297637] usb usb2: New USB device found, idVendor=1d6b, 
idProduct=0002, bcdDevice= 4.17
[ 1736.307983] usb usb2: New USB device strings: Mfr=3, Product=2, 
SerialNumber=1
[ 1736.315734] usb usb2: Product: EHCI Host Controller
[ 1736.322479] usb usb2: Manufacturer: Linux 4.17.10-ak+ ehci_hcd
[ 1736.328582] usb usb2: SerialNumber: 48064800.ehci
[ 1736.341064] hub 2-0:1.0: USB hub found
[ 1736.351226] hub 2-0:1.0: 3 ports detected
[ 1736.731079] usb 2-2: new high-speed USB device number 2 using 
ehci-omap
[ 1736.955474] usb 2-2: New USB device found, idVendor=0af0, 
idProduct=8800, bcdDevice= 0.00
[ 1736.964324] usb 2-2: New USB device strings: Mfr=3, Product=2, 
SerialNumber=0
[ 1736.976470] usb 2-2: Product: Globetrotter HSUPA Modem
[ 1736.983062] usb 2-2: Manufacturer: Option N.V.
[ 1737.048431] hso 2-2:1.5: Not our interface