kern/129526: pxeboot fails to load kernel / modules

[Hiroharu Tamaru]

At Wed, 10 Dec 2008 14:51:48 -0500,
John Baldwin wrote:
> 
> On Wednesday 10 December 2008 04:20:31 am Hiroharu Tamaru wrote:
> > Thank you, John.
> > 
> > At Tue, 9 Dec 2008 16:21:47 -0500, John Baldwin wrote:
> > >
> > > On Tuesday 09 December 2008 12:54:06 pm Hiroharu Tamaru wrote:
> > (snip)
> > > > It turns out that replacing the pxeboot binary served by tftp
> > > > to pxeboot in 6.4-RELEASE-i386-bootonly.iso allows the installer
> > > > to boot properly, but pxeboot from 7.0-RELEASE also fails.
> > > > 
> > > > It then turned out that by unzipping the /boot/mfsroot.gz image
> > > > on the ftp server, it allows the kernel to boot, for any of the 
> pxeboot's
> > > > mentioned above.
> > > > 
> > > > Thus, it seems likely that the unzipping routines in pxeboot,
> > > > or more precisely, the loader included in the pxeboot,
> > > > is corrupting some part of the device table or such.
> > (snip)
> > > I think loader has just grown and the stack is growing into the heap.  
> There 
> > > is a loader option to move the heap up above 1 MB that you should try.
> > 
> > Indeed, it was.
> > 
> > (for the record:)
> > Enabling the code in sys/boot/i386/loader/main.c
> > that is activated by putting either of:
> >  LOADER_BZIP2_SUPPORT=yes
> >  LOADER_FIREWIRE_SUPPORT=yes
> >  LOADER_ZFS_SUPPORT=yes  (8.0-current only ATM)
> > into /etc/make.conf has solved the problem.
> > 
> > 
> > Current pxeboot build pulls the loader binary built for
> > the (non-pxe-)loader verbatim.
> > 
> > Is there a possibility that putting the heap above 1MB
> > might become the default in the near future? say, whenever
> > LOAD_NO_GZIP_SUPPORT is not set.
> > 
> > Alternatively, do you think it is worth a trouble to modifiy
> > the build system so that the default pxeboot has this high
> > heap support?
> > 
> > Or, would you think whoever setting up an pxeboot installer
> > should know the corners, and either unzip the mfsroot.gz or
> > rebuild his own pxeboot?
> 
> I think adding GPT support (which I did) probably caused the loader to grow 
> enough in size.  Probably I should make the GPT stuff optional and enable the 
> higher memory usage if it is enabled (but make it on by default perhaps?)

I agree that's quite reasonable (wrapping around GPT, and default it to on).

I looked into the sources, but to me, wrapping all the bits on GPT with
#ifdef LOADER_GPT_SUPPORT was not too trivial.
How trivial or non-trivial is it if I asked you for it?
I'll look into it again when I get another time slot if 
you are too busy until then.

Thanks.

Hiroharu