[syslinux] Fedora 21 extlinux 6.03 boot failure

[Ady]

> I am aware of that.  It doesn't change the fact that the system does not
> boot a Fedora 21 partition with syslinux 6.03 and does boot it successfully
> when using the bootloader from 4.05.
> 
 
The mismatch version of c32 modules is relevant in some cases because the error 
message is not so clear / evident (especially considering that c32 modules do not 
contain any version info). Before launching the kernel, your config is already 
trying to load menu.c32. In theory, you are correct in that it doesn't seem to be 
important in this particular case. I would tend to think that, in practice, we 
should simplify as much as possible the environment so to narrow down the (source 
of the) problem, and "going by the book" (e.g. not mixing versions of 
Syslinux-related files) is always recommended when troubleshooting.

If we could just catch the problem so easily we wouldn't need troubleshooting :). I 
would suggest commenting out the UI and the TIMEOUT directives. Since you have no 
DEFAULT directive, there might be some kind of warning message when getting to the 
Syslinux boot prompt (after commenting out the UI directive and rebooting), but 
that's not really important in this case.

Then you could launch the respective label from the CLI. Additional simplifications 
for troubleshooting could be:
_ Using only lower-case for labels ("linux1" instead of "Linux1").
_ Using simpler file names for labels, kernel files and initrd files (instead of 
using multiple dots, hyphen symbols, long names,...). I tend to use basic "8.3" for 
troubleshooting (certainly no spaces, no "-", no "1.2.3.c-test_moretext", only 
English basic characters...).
_ Using the "LINUX" keyword instead of the generic "KERNEL" keyword ("LINUX 
mykernel" instead of "KERNEL mykernel").
_ Using short paths with short directory names (up to 11 basic english characters, 
no dots, no symbols, no spaces) (you are already using the root "/" of the 
partition for kernel and initrd files, and "/boot/extlinux/" for Syslinux-related 
files, including the c32 modules in the latter, so you should be OK in this 
regard).
_ Avoiding (sym)links for troubleshooting.
_ Simplifying as much as possible the extlinux.conf (e.g. 2 simple entries, no 
timers, no c32 modules being called from it, no "left-over" directives, no global 
directives, always using labels, CLI only...).

There are some additional possibilities, depending on the type of problem. For 
instance, sometimes the problem is between the kernel and the hardware, or the 
configuration settings when the kernel was built (e.g. relocatable, or not), so 
testing the same hardware with different kernels could be useful in some cases.

As already mentioned, updating the firmware (BIOS) is part of troubleshooting.

There are more possible steps; let's hope we don't need them.
 
 
> > > If I then reboot the system, it is able to boot into either Fedora 19 or
> > > Fedora 21 without any problems.  It is true that I do get some minor
> > > complaints:
> > > 
> > >    SYSLINUX 4.05 2011-12-09 Copyright (C) 1994-2011 H. Peter Anvin et al
> > >    menu.c32: not a COM32R image
> > >    boot: 
> >  
> > The reason being a mismatch version between the c32 modules and the version of the 
> > bootloader.
> 
> Yes, of course, but that's not a significant problem.  The system still boots.
 
See prior comments above.
 
> 
> > > I don't think it's a mismatch issue.  I have followed the same scripted
> > > procedure many times without any problems.
> >  
> > But until now you were updating versions of Syslinux up to 4.xx. The mismatch 
> > version problems were less evident then (more "tolerance" was "accepted"), but 
> > since Syslinux v.5+, the mismatch version problem is much more relevant and even a 
> > minor mismatch version (e.g. other package claiming to use the same version) might 
> > cause problems.
> 
> I guess I wasn't clear.  I have followed the same procedure for 22 different
> Fedora 19 to Fedora 21 upgrades.  In each case, I went from 4.05 to 6.03.
> Only this one machine is misbehaving.  It is presumably, therefore, related
> to a hardware issue.
 
You were clear; I just thought you were referring to prior updates in that 
paragraph, from even older versions of Fedora, when the Syslinux version was even 
older than v4.05.
 
> 
> > Anyway, the serial console is one immediate point for review (please post your
> > entire extlinux.conf).
> 
> I posted it above.  Why is the serial console an "immediate point for review"?
> Almost all of my systems use serial consoles, although most are using
> IPMI over serial redirection.  This one uses a physical serial connection,
> since the baseboard does not have IPMI 2.0 support.
 
Well, you were an important part of our previous discussion about the SERIAL 
console, which triggered the recent patch for octal and hex values. That was not 
the first time the serial console was showing some problem. My hunch (calling it 
that way because I cannot prove it in a consistent replicable way since I lack the 
knowledge and skills to do it) is that we will eventually find more issues with the 
serial console / output / directive (and anything related to them).
 
 
> 
> > The BIOS version might matter because Syslinux v.6.xx could be triggering a problem 
> > in buggy BIOS versions, whereas v.4.xx was not triggering the same problem. We have 
> > seen this before; after the BIOS update the same version of Syslinux might succeed.
> 
> That's a fair point.  I will try to upgrade the BIOS next week.
> 
> > > The completely vanilla 6.03 setup fails to boot.  The problem is that there
> > > is no error message, so it's very hard to troubleshoot.
> >  
> > You mean "vanilla" as the Syslinux-related packages from Fedora 21, not upstream 
> > Syslinux pre-built binaries downloaded from kernel.org, which _might_ (or might 
> > not) give a different result. Again, please do not forget to update the c32 files 
> > too from the same origin of the bootloader you are actually installing in the VBR. 
> > Mixing files from one package with others from another one (even if they are both 
> > the same "version") is unwanted for troubleshooting.
> 
> Correct.  I am using the Fedora package.  If a BIOS upgrade doesn't fix the
> problem, I will try the official syslinux binaries.  I will also try grub2.
> 
 
Any chance you could test other kernels too? This would be another troubleshooting 
possibility.
 
> > There might be some commit after v.6.03 that might help too, but let's start with 
> > the easier steps.
> 
> Thanks for your suggestions.
> 
> -Andy
 
Thank you for the feedback.

Regards,
Ady.

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