calling my C function in entry.S...

From: Min Lee (abraxsus_at_yonsei.ac.kr.NOSPAM)
Date: 07/26/04 

Date: Mon, 26 Jul 2004 13:56:18 +0900

I modified my entry.S to call my C function myrecord, which has only some
printks.
The function myrecord is marked as asmlinkage, of course.
I inserted 3 lines before "call *sys_call_table(,%eax,4) like this...

syscall_call:

 cmpl $0, myswitch
 je continue # Min Lee
 call myrecord
continue:

 call *sys_call_table(,%eax,4)
 movl %eax,EAX(%esp) # store the return value

After my dummy system call sets the global var myswitch to 1, which enables
calls to myrecord, it soon causes init process to halt!
the result is...

INIT: PANIC: segmentation violation at 0xffffe449! sleeping for 30 seconds.

But when I move my stuffs after "call *sys_call_table(,%eax,4)" , it works!

syscall_call:

 call *sys_call_table(,%eax,4)
 movl %eax,EAX(%esp) # store the return value

 cmpl $0, myswitch
 je continue # Min Lee
 call myrecord
continue:

What's wrong with the first trying?
What's the difference between calling myrecord function before and after
"call *sys_call_table" ??