Re: 2.6.23-rc1: i386 section mismatch warnings

[Sam Ravnborg <sam@ravnborg.org>]

On Mon, Jul 23, 2007 at 09:18:38PM -0400, Jeff Garzik wrote:
> make allmodconfig on i386:
> 
> WARNING: vmlinux(.text+0xc0101183): Section mismatch: reference to 
> .init.text:start_kernel (between 'is386' and 'check_x87')
> WARNING: vmlinux(.text+0xc02cfcdb): Section mismatch: reference to 
> .init.text:kernel_init (between 'rest_init' and 'kthreadd_setup')
> WARNING: vmlinux(.text+0xc02d5ed2): Section mismatch: reference to 
> .init.text: (between 'iret_exc' and '_etext')
> WARNING: vmlinux(.text+0xc02d5ede): Section mismatch: reference to 
> .init.text: (between 'iret_exc' and '_etext')
> WARNING: vmlinux(.text+0xc02d5eea): Section mismatch: reference to 
> .init.text: (between 'iret_exc' and '_etext')
> WARNING: vmlinux(.text+0xc02d5ef6): Section mismatch: reference to 
> .init.text: (between 'iret_exc' and '_etext')
> WARNING: vmlinux(.text+0xc02cfda4): Section mismatch: reference to 
> .init.text:__alloc_bootmem_node (between 'alloc_node_mem_map' and 
> 'zone_wait_table_init')
> WARNING: vmlinux(.text+0xc02cfe4e): Section mismatch: reference to 
> .init.text:__alloc_bootmem_node (between 'zone_wait_table_init' and 
> 'vgacon_scrollback_startup')
> WARNING: vmlinux(.text+0xc02d64c6): Section mismatch: reference to 
> .init.text: (between 'iret_exc' and '_etext')
> WARNING: vmlinux(.text+0xc02cfea7): Section mismatch: reference to 
> .init.text:__alloc_bootmem (between 'vgacon_scrollback_startup' and 
> 'fb_find_logo')
> WARNING: vmlinux(.text+0xc02cfecb): Section mismatch: reference to 
> .init.data:logo_linux_mono (between 'fb_find_logo' and 'schedule')
> WARNING: vmlinux(.text+0xc02cfed5): Section mismatch: reference to 
> .init.data:logo_linux_clut224 (between 'fb_find_logo' and 'schedule')
> WARNING: vmlinux(.text+0xc02cfeda): Section mismatch: reference to 
> .init.data:logo_linux_vga16 (between 'fb_find_logo' and 'schedule')
> WARNING: vmlinux(.text+0xc02d6612): Section mismatch: reference to 
> .init.text: (between 'iret_exc' and '_etext')

The above warnings happens because during final link we stuff
a lot of different sections down in a smaller number of sections.
So modpost does not know that the references are actually OK.

The fix is simply to avoid doing section mismatch check on vmlinux
when processing the modules and I have this in kbuild.git.
I expect this to be merged during -rc1 (was sent in the merge window
but did not get applied).

As a general rule just ignore all section mismatch warnings that originate
from vmlinux. The others needs to be fixed and there seem to be enough
to deal with :-(

	Sam