OpenMarine

The file log: syslog + kern + messages expand continuously and occupy 1 GB per day:

Aug 10 19:57:22 etta2 kernel: [ 7662.738061]
Aug 10 19:57:22 etta2 kernel: [ 7662.752098] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.752098]
Aug 10 19:57:22 etta2 kernel: [ 7662.786062] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.786062]
Aug 10 19:57:22 etta2 kernel: [ 7662.800064] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.800064]
Aug 10 19:57:22 etta2 kernel: [ 7662.822181] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.822181]
Aug 10 19:57:22 etta2 kernel: [ 7662.826055] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.826055]
Aug 10 19:57:22 etta2 kernel: [ 7662.826174] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.826174]
Aug 10 19:57:22 etta2 kernel: [ 7662.830058] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.830058]
Aug 10 19:57:22 etta2 kernel: [ 7662.834049] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.834049]
Aug 10 19:57:22 etta2 kernel: [ 7662.834161] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.834161]
Aug 10 19:57:22 etta2 kernel: [ 7662.838054] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.838054]
Aug 10 19:57:22 etta2 kernel: [ 7662.838161] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.838161]
Aug 10 19:57:22 etta2 kernel: [ 7662.840047] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.840047]
Aug 10 19:57:22 etta2 kernel: [ 7662.850063] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.850063]
Aug 10 19:57:22 etta2 kernel: [ 7662.862057] WARN::dwc_otg_handle_mode_mismatch_intr:68: Mode Mismatch Interrupt: currently in Host mode
Aug 10 19:57:22 etta2 kernel: [ 7662.862057]

This seems related to an USB device connected to your raspberry.

Could you add more data about your environment? RPI model, OP version, connected devices, OP settings...

Do you have a HUB?
https://github.com/raspberrypi/linux/issues/2408

I have RPi3 with Op 1.1 and hub too
And:
mouse
wireless keyboard
usb memory
victron BMV 701
Huawey 4G router (usb connected)
micro sd adapter
usb-nmea interface