Most recent kernel where this bug did not occur:??
Distribution:2.6.22.6
Hardware Environment:
# cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 1
model name      : Intel(R) Pentium(R) 4 CPU 1.70GHz
stepping        : 2
cpu MHz         : 1703.943
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm up
bogomips        : 3411.31

Software Environment:
/proc/version :
Linux version 2.6.18.4 (root@debian) (gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)) #1 SMP Sat Sep 22 07:27:59 IST 2007 

Problem Description:
compilation ERROR: "kdb_8250" [drivers/serial/8250.ko] undefined! // 2.6.22.6 

Steps to reproduce: 

make bzImage //OK 
make modules 



Building modules, stage 2.
  MODPOST 2106 modules
WARNING: vmlinux(.text+0xc010116f): Section mismatch: reference to .init.text:start_kernel (between 'is386' and 'check_x87')
WARNING: vmlinux(.text+0xc02d8abb): Section mismatch: reference to .init.text: (between 'rest_init' and 'alloc_node_mem_map')
WARNING: vmlinux(.text+0xc02deb2f): Section mismatch: reference to .init.text: (between 'iret_exc' and '_etext')
WARNING: vmlinux(.text+0xc02deb3b): Section mismatch: reference to .init.text: (between 'iret_exc' and '_etext')
WARNING: vmlinux(.text+0xc02deb47): Section mismatch: reference to .init.text: (between 'iret_exc' and '_etext')
WARNING: vmlinux(.text+0xc02deb53): Section mismatch: reference to .init.text: (between 'iret_exc' and '_etext')
WARNING: vmlinux(.text+0xc02d8b40): Section mismatch: reference to .init.text:__alloc_bootmem_node (between 'alloc_node_mem_map' and 'zone_wait_table_init')
WARNING: vmlinux(.text+0xc02d8bea): Section mismatch: reference to .init.text:__alloc_bootmem_node (between 'zone_wait_table_init' and 'setup_cpu_cache')
WARNING: vmlinux(.text+0xc02d8c6a): Section mismatch: reference to .init.text: (between 'setup_cpu_cache' and 'schedule')
WARNING: vmlinux(.text+0xc02d8ca4): Section mismatch: reference to .init.text: (between 'setup_cpu_cache' and 'schedule')
WARNING: vmlinux(.text+0xc0207560): Section mismatch: reference to .init.text:__alloc_bootmem (between 'vgacon_startup' and 'vgacon_scrolldelta')
WARNING: vmlinux(.text+0xc02df28d): Section mismatch: reference to .init.text: (between 'iret_exc' and '_etext')
ERROR: "kdb_8250" [drivers/serial/8250.ko] undefined!
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2