symbols, no symbols, symbols ...

I'm hacking around a module but I have the following problem:

- I worked around to get my hands on sys_call_table and succeded but

module_A: definition of new symbol new_sys_call_table, and of replacement new_sys_read, new_sys_write, new_sys_open, new_sys_close, new_sys_lseek. If I use them inside module_A THEY WORK FINE.

module_B: module_A is loaded, symbols appear in "cat /proc/ksyms |grep new_sys_" but they return error (work but return -9=-EBADF, read/write).

What am I doing wrong? Why do they work fine inside module_A and not get imported right in module_B?

Thanks ...