[syslinux] IPMI serial over lan disconnects seem to trigger extlinux reboots

H. Peter Anvin hpa at zytor.com
Mon Nov 11 20:00:47 PST 2013


On 11/11/2013 05:38 PM, Andrew J. Schorr wrote:
> Hi,
> 
> I hope somebody can help me with this problem.  I don't know whether
> it's a problem with my configuration or a bug or feature in extlinux.
> I am using an IPMI 2.0 serial-over-lan console to connect to a system
> with an Intel S3200SHL motherboard.  The first line of my extlinux.conf
> file looks like this:
>    serial 0 57600 0x003
> I am using ipmitool to access the console, like so:
>    ipmitool -f /etc/ipmi.passwd -U <user> -I lanplus -H <host> sol activate
> 
> I just converted this system from grub 0.97 to extlinux 4.05.  The IPMI BMC
> software on this system is pretty flaky.  The IPMI serial-over-lan session
> disconnects frequently, particularly during the boot process.  After converting
> to extlinux, it looks to me as if the extlinux loader reboots the system
> whenever the IPMI serial console disconnects.  This often happens while
> extlinux is loading the kernel or the initrd.  As a result, it can reboot
> itself many times before it gets lucky and makes it far enough to hand off
> control to the kernel.  Once the kernel takes over, there is no problem -- it
> doesn't mind the disconnects.
> 
> This problem did not occur with grub.  My question is whether there is some
> serial flag configuration that would tell extlinux to ignore the disconnects,
> or would it require a patch to the software to achieve that?
> It is not obvious to me from reading the description of the serial flag
> values whether I could somehow fix the problem that way.  I tried searching
> the source code, but I was unable to find the relevant bits.
> 
> Does anybody know how to solve this problem?
> 

There is no reason by Syslinux would reboot the system on a serial
disconnect.  There could be a bug, of course; now, Syslinux 4.05 is
pretty old so unless you can reproduce this on a current version that
would be useful.

The other option is that there is something in the IPMI BC that causes
the reboots which happens on Syslinux and not Grub for some reason.

You may want to turn serial interrupts on (serial 0 57600 0x00b) and see
if that makes any difference.

	-hpa



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