Re: Shutdown -r under -current hangs on RPi3

On Sun, Sep 24, 2023 at 08:17:54AM -0700, bob prohaska wrote:
> 
> It appears that setting 
> debug.bootverbose=1 
> suppresses the otherwise-persistent
> Khelp module "ertt" can't unload until its refcount drops from 1 to 0.
> message during shutdown. No new output either, apart from the swap
> removal notice.
> 
> So far, the few shutdown -r experiments tried have not gotten stuck,
> even after an OS build/install cycle.

Another shutdown hang has been observed with -current on a Pi3.
This time bootverbose was on, as was ucom debug. This machine
has an FTDI usb-serial adaper. 

The serial console reported:

*** FINAL System shutdown message from bob@pelorus.zefox.org ***             

System going down IMMEDIATELY                                                  

                                                                               
Oct  1 08:21:26 pelorus shutdown[78571]: reboot by bob: 
Stopping sshd.
Waiting for PIDS: 1063.
Stopping cron.
Waiting for PIDS: 1073.
Stopping powerd.
Waiting for PIDS: 1002.
Stopping devd.
Waiting for PIDS: 752.
Writing entropy file: .
Writing early boot entropy file: .
.
Terminated
ucom_inwakeup: tp=0xffffa00021cc1c00
ucom_ioctl: cmd = 0x2000740e
ucom_inwakeup: tp=0xffffa00021cc1c00
ucom_inwakeup: tp=0xffffa00021cc1c00
ucom_close: tp=0xffffa00021cc1c00
ucom_shutdown: 
ucom_dtr: onoff = 0
ucom_line_state: on=0x00, off=0x01
ucom_rts: onoff = 1
ucom_line_state: on=0x02, off=0x00
Oct  1 08:21:32 pelorus ucom_cfg_close: 
syslogd: exiting on signal 15
Waiting (max 60 seconds) for system process `vnlru' to stop... done
Waiting (max 60 seconds) for system process `syncer' to stop... 
Syncing disks, vnodes remaining... 0 0 0 done
All buffers synced.
Swap device da0s2b removed.
Uptime: 3d0h14m47s
Resetting system ... 

Both Ethernet LEDs turned off, if that's significant.
After about half an hour, I pulled the plug. The machine
came up hands-off.

Thanks for reading,

bob prohaska