Fw: [syslinux] Issue with pxelinux

Andrew Wray andywray at us.ibm.com
Tue Sep 13 12:09:49 PDT 2005





I've been working with Matt Burgess here on this problem, and have found
the following:

syslinux 3.08-pre10 — broken
>>> config.inc:max_cmd_len=255

syslinux 3.08-pre11 — works
>>> config.inc:max_cmd_len=1023

syslinux 3.08 — works
>>> config.inc:max_cmd_len=1023

syslinux 3.09-pre1 — works
>>> config.inc:max_cmd_len=1023

syslinux 3.09-pre2 — broken (repeatedly enters pxeboot*)
>>> config.inc:max_cmd_len=511

We actually changed the define from 511 to 1023 in version 3.09-pre2 and
recompiled, and the problem with the system hanging on "localboot 0" did
not occur then.

Also, this happens on the following systems:

IBM 8837 (x336), which has Broadcom PXE ROM 2.1 v7.7.6
IBM 8843 (HS20), which has Broadcom PXE ROM 2.1 v7.6.6

but not on

IBM 8848 (e326), which has Broadcom PXE ROM 2.1 (build 082) v7.0.3

I've been trying to go through the code, but I'm not doing a very good job
of following it.  I'm guessing some kind of variable overflow or something
may be causing this problem, but I can't pin down where it is in the code,
or why it behaves differerntly on different systems.

I realize that this is not a problem in the latest version of pxelinux, but
I'd like to understand the cause of this problem, as if its a BIOS/PXE ROM
issue, I'd like to get those fixed, but if its a pxelinux problem,
understanding it would help keep the problem from being re-introduced in
the future.


Any help that could be provided on this would be greatly appreciated,

Andy Wray
e1350 Linux Cluster System Test
IBM, RTP



On 8/31/05, Geert Stappers <stappers at stappers.nl> wrote:
>
> On Tue, Aug 30, 2005 at 03:04:22PM -0400, Matt Burgess wrote:
> > Mr. Anvin,
> >
> > I have noticed that PXELINUX release 3.10 has fixed this issue. Is this
> > something you did explicitly, or was it by chance? Out of curiosity,
> what
> > was the fix?
> >
> > Thanks for your help,
> >
> > Matt Burgess
> >
> > On 6/27/05, H. Peter Anvin <hpa at zytor.com> wrote:
> > >
> <snip/>
> > > >
> > > > Any help with this would be greatly appreciated.
> > > >
> > >
> > > Since you, unlike me, have access to the hardware, it would be better

> if
> > > you could try some debugging, including figure out exactly which
> > > prerelease broke the setup.
>
> Figure out which prerelease fixed the setup.
> (and reply below the text)
>
>
> Cheers
> Geert Stappers



Thanks for your help with all of this,

I have done some more testing with this and this is what I have found:

(note that if no behavior is given for "broken", assume does not exit
pxeboot)

syslinux < 3.00 — works
syslinux 2.20-pre7 — works (never an official 2.20 release)
syslinux 2.20-pre8 — broken
...
...
syslinux 3.07 — broken

syslinux 3.08-pre1 — broken
syslinux 3.08-pre2 — broken
syslinux 3.08-pre3 — broken
syslinux 3.08-pre4 — broken
syslinux 3.08-pre5 — broken
syslinux 3.08-pre6 — broken
syslinux 3.08-pre7 — broken
syslinux 3.08-pre8 — broken
syslinux 3.08-pre9 — broken
syslinux 3.08-pre10 — broken
syslinux 3.08-pre11 — works

syslinux 3.08 — works

syslinux 3.09-pre1 — works
syslinux 3.09-pre2 — broken (repeatedly enters pxeboot*)

syslinux 3.09 — broken (repeatedly enters pxeboot)

syslinux 3.10-pre1 — broken
syslinux 3.10-pre2 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre3 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre4 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre5 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre6 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre7 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre8 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre9 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre10 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre11 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre12 — broken (doesn't prompt and repeatedly enters pxeboot)
syslinux 3.10-pre13 — broken (repeatedly enters pxeboot)
syslinux 3.10-pre14 — works
syslinux 3.10-pre15 — works
syslinux 3.10-pre16 — works
syslinux 3.10-pre17 — works
syslinux 3.10-pre18 — works
syslinux 3.10-pre19 — works
syslinux 3.10-pre20 — works
syslinux 3.10-pre21 — works

syslinux 3.10 — works


syslinux 3.11-pre10 — works

* Tell pxelinux to boot from localdisk and it goes through the whole
process
again... tftp's pxelinux.0, etc repeatedly and continuously




This is what the pxelinux.cfg/default config file looks like:

timeout 0
default local
display pxelinux.cfg/messages/default
prompt 1
implicit 0
label local
localboot 0
label exit
localboot 0


Again, thanks for the help on this,

Matt Burgess
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