qmi-proxy hangs / keeps open during shutdown / reboot
[ OK ] Reached target Shutdown.
[ OK ] Reached target Final Step.
[ OK ] Started Power-Off.
[ OK ] Reached target Power-Off.
[ 285.640686] printk: systemd-shutdow: 52 output lines suppressed due to ratelimiting
[ 285.690524] systemd-shutdown[1]: Syncing filesystems and block devices.
[ 285.748499] systemd-shutdown[1]: Sending SIGTERM to remaining processes...
[ 285.765379] systemd-journald[279]: Received SIGTERM from PID 1 (systemd-shutdow).
[ 363.615165] INFO: task qmi-proxy:534 blocked for more than 120 seconds.
[ 363.621812] Not tainted 5.4.0-next-20191203-librem5-00005-g589ded0936f7 #14
[ 363.629337] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 363.637388] qmi-proxy D 0 534 1 0x0000082d
[ 363.642891] Call trace:
[ 363.645359] __switch_to+0xc0/0x210
[ 363.648878] __schedule+0x288/0x5a8
[ 363.652380] schedule+0x48/0x100
[ 363.655627] wdm_flush+0xe8/0x128 [cdc_wdm]
[ 363.659840] filp_close+0x3c/0x90
[ 363.663170] put_files_struct+0x110/0x118
[ 363.667192] exit_files+0x44/0x58
[ 363.670512] do_exit+0x2a8/0x9f8
[ 363.673767] do_group_exit+0x48/0xa8
[ 363.677357] get_signal+0xec/0x828
[ 363.680772] do_notify_resume+0x30c/0x468
[ 363.684808] work_pending+0x8/0x14
[ 375.764807] systemd-shutdown[1]: Sending SIGKILL to remaining processes...
[ 375.778374] systemd-shutdown[1]: Sending SIGKILL to PID 534 (qmi-proxy).
[ 465.789929] systemd-shutdown[1]: Unmounting file systems.
[ 465.798316] [757]: Remounting '/' read-only in with options 'errors=remount-ro'.
[ 465.818562] [757]: Failed to remount '/' read-only: Device or resource busy
[ 465.826512] systemd-shutdown[1]: Not all file systems unmounted, 1 left.
[ 465.833311] systemd-shutdown[1]: Deactivating swaps.
[ 465.838471] systemd-shutdown[1]: All swaps deactivated.
[ 465.843737] systemd-shutdown[1]: Detaching loop devices.
[ 465.852775] systemd-shutdown[1]: All loop devices detached.
[ 465.858375] systemd-shutdown[1]: Detaching DM devices.
[ 465.863722] systemd-shutdown[1]: All DM devices detached.
[ 465.870004] systemd-shutdown[1]: Unmounting file systems.
[ 465.877736] [758]: Remounting '/' read-only in with options 'errors=remount-ro'.
[ 465.885347] [758]: Failed to remount '/' read-only: Device or resource busy
[ 465.893069] systemd-shutdown[1]: Not all file systems unmounted, 1 left.
[ 465.965278] reboot: Power downand qmi-network /dev/cdc... stop doesn't help and I'm not successful in killing qmi-proxy currently.