access pointer and global variables

[Wenji Huang]

  Hi guru,

    I just began to know about the project and ran into some problems.

    a. dereference pointer
       probe kernel.function("schedule").return{
          $prev can be accessed, but just treated as long type
          $prev->pid can't be accessed
        }
   
    b. Global variable
        how to get the value of global variables, seems that only local 
variables are accessible in probe point.

    c. char *
        probe kernel.function("sys_open") {
           //parameter list in source:   const char __user *filename, 
int flags, int mode)  

           $filename can be accessed, but how to get the string of 
filename point ?
        }

Thanks in advance!
*
Wenji*