Precise Pangolin shutdown fails from serial console

[Michael Paoli]

Ubuntu 12.04 LTS "Precise Pangolin" - Alpha i386 (20120318)
bug reproducible as follows (my comments on lines starting with //):
//boot image from ISO
//at (graphic) prompt on graphics console to configure options, hit spacebar on keyboard
//hit <ENTER> to select English
//hit <F6> for Other Options
//hit <ESC> to dismiss apci, etc. set of options
//type the following to append to Boot Options command line:
console=tty0 console=ttyS0,9600n8
//hit <ENTER> to boot
//after boot completes,
//hit <Ctrl+Alt+F1> for first virtual (text) console, then enter (prompts also shown):
ubuntu@ubuntu:~$ cd / && exec sudo su -
root@ubuntu:~# cd /etc/init/
//for proper permissions/ownerships:
root@ubuntu:/etc/init# cp -p tty1.conf ttyS0.conf
root@ubuntu:/etc/init# < tty1.conf > ttyS0.conf sed -e 's/tty1/ttyS0/g'
root@ubuntu:/etc/init# telinit q
root@ubuntu:/etc/init# start ttyS0 && cd / && clear && logout
//then from serial console connection, showing full input and output:
Welcome to Ubuntu precise (development branch) (GNU/Linux 3.2.0-19-generic-pae i686)

 * Documentation: https://help.ubuntu.com/

ubuntu@ubuntu:~$ cd / && exec sudo su -
root@ubuntu:~# cd / && exec shutdown -h -P now
Checking for running unattended-upgrades:
acpid: exiting
speech-dispatcher disabled; edit /etc/default/speech-dispatcher
 * Asking all remaining processes to terminate... [ OK ]
 * All processes ended within 2 seconds.... [ OK ]
modem-manager[1049]: <info> Caught signal 15, shutting down...

 * Deconfiguring network interfaces... [ OK ]
 * Unmounting temporary filesystems... [ OK ]
 * Deactivating swap... [ OK ]
 * Stopping remaining crypto disks... [ OK ]
 * Stopping early crypto disks... [ OK ]
umount: /run/lock: not mounted
[ 563.332557] ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6
[ 563.333353] ata2.00: cmd a0/00:00:00:08:00/00:00:00:00:00/a0 tag 0 pio 16392 in
[ 563.333354] res 01/60:00:00:08:00/00:00:00:00:00/a0 Emask 0x3 (HSM violation)
[ 563.335272] ata2.00: status: { ERR }

//the (persumably) kernel diagnostic lines above
//starting with the ... "ata2.00: exception Emask" ... line through the blank line above
//appear on both serial (ttyS0) and graphics (tty0/tty1) console,
//after which system is quite solidly hung at that point

//comparatively, essentially the same procedure works fine and without error on:
//Ubuntu 10.04.3 LTS "Lucid Lynx" - Release i386 (20110720.1)
//ending with prompt of:
Please remove the disc and close the tray (if any) then press ENTER:

//displayed on both serial (ttyS0) and graphics (tty0/tty1) console,
//and then striking <ENTER> on the serial console (selected as primary per boot options)
//then completes the power down as expected:

 * Will now halt
                [ 279.290176] Power down.

//and system then powers down,
// but on
//Ubuntu 12.04 LTS "Precise Pangolin" - Alpha i386 (20120318)

//We also need:
//
//1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu
//with straight ISO images:
//fails on: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha i386 (20120318)
//works on: Ubuntu 10.04.3 LTS "Lucid Lynx" - Release i386 (20110720.1)
//2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center
//see above
//3) What you expected to happen
//expected "normal" shutdown to complete - in the case of booted from
//ISO, prompt to "remove the disk and close the tray" and then after
//responding to that prompt, final system shutdown
//4) What happened instead
//apparently kernel errors and hung system
//it looks like the kernel hits some serious snags before making it that far along in the shutdown.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/958838/+editstatus and add the package name in the text box next to the word Package.

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