kern/129526: pxeboot fails to load kernel / modules

[John Baldwin]

The following reply was made to PR kern/129526; it has been noted by GNATS.

From: John Baldwin <jhb at freebsd.org>
To: Hiroharu Tamaru <tamaru at myn.rcast.u-tokyo.ac.jp>
Cc: sobomax at freebsd.org, pjd at freebsd.org, FreeBSD-gnats-submit at freebsd.org,
        freebsd-bugs at freebsd.org
Subject: Re: kern/129526: pxeboot fails to load kernel / modules
Date: Wed, 10 Dec 2008 14:51:48 -0500

 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?)
 
 -- 
 John Baldwin