Understand a semantic error in this simplistic kernel function counter script

[FOPA Leon constantin]

Hi,

I am writing a systemTap script to count the number of time the 
free_hot_page kernel function is call during every 5 seconds.
The simplistic version of the code is the following :

global free_hot_page

probe kernel.function("free_hot_page"){
       free_hot_page <<< 1
}

probe timer.s(5) {
       free_hot_page <<< 0

       hsum = @sum(free_hot_page)

       printf("%29s %13d\n", tz_ctime(gettimeofday_s()), hsum)

       delete free_hot_page
}

However, running this simple code produce semantic error (see below).
What does this error means and how to fix the problem ?

Best regards,

semantic error: while resolving probe point: identifier 'kernel' at 
count-page-cache-release.stp:13:7
         source : probe kernel.function("free_hot_page"){
                       ^

semantic error: no match (similar functions: free_arg_page, 
free_huge_page, free_one_page, free_p2m_page, __free_one_page)

Pass 2: analysis failed.  [man error::pass2]