Re: 2.4.25-rc1: BUG: wrong zone alignment, it will crash

["Randy.Dunlap" <rddunlap@osdl.org>]

On Sat, 7 Feb 2004 00:46:31 +0800 Michael Frank <mhf@linuxmail.org> wrote:

| On Friday 06 February 2004 23:36, Rik van Riel wrote:
| > On Fri, 6 Feb 2004, Michael Frank wrote:
| > 
| > > > > 300MB HIGHMEM available.
| > > > > 195MB LOWMEM available.
| > > > > On node 0 totalpages: 126960
| > > > > zone(0): 4096 pages.
| > > > > zone(1): 46064 pages.
| > > > > zone(2): 76800 pages.
| > > > > BUG: wrong zone alignment, it will crash
| > 
| > > It is supposed to work, just a bug in the zone alignment code.
| > 
| > The error isn't in the kernel, it's between the chair and the keyboard.
| > You have created a lowmem zone of a size that doesn't correctly
| > align with the largest blocks used by the buddy allocator.
| > 
| > > I have have to use HIGHMEM emulation for testing.
| > 
| > Then you'll need to choose a different size for the highmem=
| > parameter, one that doesn't cause an unaligned boundary.
| 
| Which is not user friendly and does not match the documentation.

Interesting boot option... but what doc. are you referring to?


| > Alternatively, you could submit a patch so the highmem= boot
| > option parsing code does the aligning for you.
| 
| OK, will do. I'll produce and test a patch.

Please include an update to Documentation/kernel-parameters.txt .

| > However, that would simply be an improvement to the kernel and
| > nothing like a bug you can demand to get fixed now.
| 
| OK, Please note that I only passed on the message produced by the kernel 
|   BUG: wrong zone alignment, it will crash 
| 
| Perhaps the kernel should have reported it as "Invalid value for highmem" 
| instead of "BUG" ;)

How does this option work?  Does it just fake highmem_pages of
low memory as being in high memory?

--
~Randy
kernel-janitors project:  http://janitor.kernelnewbies.org/