Re: [Bug 11046] New: Kernel bug in mm/bootmem.c on Sparc machines

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 23 Jul 2008 20:25:33 -0700 (PDT) David Miller <davem@davemloft.net> wrote:

> From: Andrew Morton <akpm@linux-foundation.org>
> Date: Sun, 6 Jul 2008 13:20:49 -0700
> 
> > On Sun,  6 Jul 2008 13:02:28 -0700 (PDT) bugme-daemon@bugzilla.kernel.org wrote:
> > 
> > > http://bugzilla.kernel.org/show_bug.cgi?id=11046
>  ...
> > > Here is the BUG:
> > > 
> > > [    0.000000] PROMLIB: Sun IEEE Boot Prom 'OBP 4.11.5 2003/11/12 10:40'
> > > [    0.000000] PROMLIB: Root node compatible: 
> > > [    0.000000] Linux version 2.6.25.10 (root@sparc1) (gcc version 4.1.2
> > > 20061115 (prerelease) (Debian 4.1.1-21)) #5 SMP Sun Jul 6 21:05:42 CEST 2008
> > > [    0.000000] console [earlyprom0] enabled
> > > [    0.000000] ARCH: SUN4U
> > > [    0.000000] Ethernet address: 00:03:ba:7a:f3:d6
> > > [    0.000000] Kernel: Using 2 locked TLB entries for main kernel image.
> > > [    0.000000] Remapping the kernel... done.
> > > [    0.000000] kernel BUG at mm/bootmem.c:125!
> 
> This can only happen if you attach a zero-sized initrd to the kernel.
> 
> I see platforms like x86 sometimes have explicit checks for a zero
> size to guard reserve_bootmem() and similar calls, but if that's what
> callers are all going to do doesn't it make better sense for
> reserve_bootmem_core() to just return instead of BUG on a zero size
> argument?

Sounds logical.

Johannes just rewrote the bootmem code, but from a quick read it
appears that this behaviour has been retained.

So if we're going to change it in 2.6.26, we'll need a separate patch.