Kernel 2.6.39.1-1 issues: reboot no longer working

Question

I recently upgraded from kernel 2.6.38.7-1 to 2.6.39.1-1 , and have observed that this has caused reboot to no longer work.  Specifically, issuing "reboot -n" kicks off the shutdown process ok, and I see the shutdown procedure getting broadcast to the interactive users, but this then hangs at the very last step, where it says Restarting.
This used to work fine, and I have confirmed that a downgrade back to 2.6.38.7-1 fixes this for me.  All other packages from core and extra are up-to-date as of the time of this post.
The hardware is a fit-pc2 (i.e. intel atom-based).  Is this a known upstream bug?
Last edited by stripwax (2011-06-16 20:35:25)

Answer 1

Thanks for replies.
@stlarch :  what information would be most useful?  Happy to provide whatever might be relevant.  Hopefully the below helps
1.  I use laptop-mode-tools with everything enabled even for AC power and acpi-cpufreq. 
2.  both "shutdown -r now" and "reboot" work fine if I downgrade just the kernel back to 2.6.38.7-1 .  They both don't work (i.e. hang instead of reboot) if I upgrade just the kernel to 2.6.39.1-1
3.  It's all worked out of the box for me for the last 6 months or so, and only the latest 2.6.39.1-1 kernel has this problem, hence why I suspect it's a regression.
4.  Assuming wm means window manager:  none.   I don't even have X installed.  This is purely a headless server, run unattended and rebooted (when necessary) remotely via ssh.
5.  My dmesg reports "Selecting BIOS-method for reboots."  -   regardless of kernel version  (i.e. when running both versions mentioned)
6.  No clues in the logs unfortunately leap out to me.  Let me know if there's a specific logfile that might have clues.  With both a successful reboot (on older kernel) and failed reboot (on the newer kernel) the last few lines of everything.log say the same thing:
Jun 11 16:30:33 Xxxx shutdown[1600]: shutting down for system reboot
Jun 11 16:30:33 Xxxx init: Switching to runlevel: 6
Jun 11 16:30:34 Xxxx nmbd[1060]: [2011/06/11 16:30:34.651659,  0] nmbd/nmbd.c:71(terminate)
Jun 11 16:30:34 Xxxx nmbd[1060]:   Got SIGTERM: going down...
Jun 11 16:30:35 Xxxx laptop-mode: Laptop mode
Jun 11 16:30:35 Xxxx laptop-mode: disabled, not active
Jun 11 16:30:36 Xxxx kernel: [ 1605.732274] r8169 0000:02:00.0: PME# enabled
Jun 11 16:30:36 Xxxx syslog-ng[522]: Termination requested via signal, terminating;
Jun 11 16:30:36 Xxxx syslog-ng[522]: syslog-ng shutting down; version='3.2.4'
@brebs:  As above, this works/doesn't work dependent solely on version of kernel26 package.  Is there a kernel change between those two versions that would require me changing my kernel options?   I'd like to understand what caused the regression and see if there's an upstream fix (or raise it as an upstream issue if not), rather than just a reconfiguration/workaround.