I've got an rpi3 (Linux raspberrypi 4.9.35-v7+ #1014 SMP Fri Jun 30 14:47:43 BST 2017 armv7l GNU/Linux) that intermittently hangs on reboot. I'm a bit vague on how to track down the cause since the log files seem more focused on stuff happening during startup than on reboot. When it gets stuck the monitor shows;
[ OK } Started Show Plymouth Reboot Screen [ OK ] Stopped target Network Stopping dhcpcd on all interfaces... [ OK ] Stopped target Remote target File Systems [ OK ] Stopped target Remote target File Systems (Pre). [ OK ] Stopped dhcpcd on all interfaces.
the next line would normally be;
stopped target Basic System
so I assume that is where things go awry? The log files, which are normally in chronological order, look like this;
Nov 9 11:59:02 raspberrypi kernel: [ 408.805131] sierra ttyUSB3: Sierra USB modem converter now disconnected from ttyUSB3 Nov 9 11:59:02 raspberrypi kernel: [ 408.805204] sierNov 9 11:52:00 raspberrypi rsyslogd: [origin software="rsyslogd" swVersion="8.4.2" x-pid="420" x-info="http://www.rsyslog.com"] start Nov 9 11:52:00 raspberrypi kernel: [ 0.000000] Booting Linux on physical CPU 0x0
I can see where I unplugged the cell modem at 11:59:02 on the first line and the beginnings of some new message 'sier' on the second line before I recycled the power. I'm 99% sure the pi did not hang when I unplugged the modem so that means there is nothing in the log to do with the failed reboot. And what am I to make of the fact that the final successful reboot is supposedly 7 mins before the failed one?
I'd be very grateful for clues on how to track down a failed reboot that leaves no trace of itself in the logs since the watchdog (my last line of defense) also fails to detect the lockup.