Breakpoints in modules

I am working in modframe

Inside Host, connect gdb via pts to VM. 

Inside VM,
put the module in /root/Desktop/modexperiments/mf
make the module with all debugging info
    add this line in Makefile... EXTRA_CFLAGS += -ggdb3
modframe.ko will be created

insert the module. then it will have a /sys/modules/modframe/sections/.text entry.
track that 0xf8031000
or try this
grep function_name /proc/kallsyms ... track that address

Inside Host,

copy mf directory into /root/Desktop/modexperiments/ ... so that the files are there.

Now we will add breakpoints. 

Inside VM,

echo g > /proc/sysrq-trigger
This will hand transfer to gdb in host

Inside Host,
fire up gdb in host,
  # add-symbol-file modframe.ko 0x########
               -s .data 0x########
               -s .bss   0x########
you can view listing, or put a break point b *0xf8031000

Inside VM,
or remove the modules... that will hit the breakpoint :)
Other interesting utilities
objdump is another utility (use -h flag)

 $ nm modframe.ko -- view symbols 

or

 $ objdump -t modframe.ko            (all sections)
 $ objdump -t -j data modframe.ko    (data section)
 $ objdump -t -j bss modframe.ko     (BSS section)  

Ref:

https://www.linux.com/learn/linux-career-center/33991-the-kernel-newbie-corner-

kernel-and-module-debugging-with-gdb 

http://linux-hacks.blogspot.com/2009/07/using-gdb-for-debugging-kernel-modules.html