stap error: no match while resolving probe point kernel.function("do_mmap_pgoff@mm/mmap.c:901")

[a qi]

HI,
I'm new to systemtap,   I got the follow error message :

 ./t15.stp  --vp 01
semantic error: libdw failure (dwarf_getsrc_file): no matching address range
semantic error: no match while resolving probe point
kernel.function("do_mmap_pgoff@mm/mmap.c:901")
semantic error: no probes found
Pass 2: analyzed script: 0 probe(s), 0 function(s), 0 embed(s), 0
global(s) in 140usr/80sys/219real ms.
Pass 2: analysis failed.  Try again with another '--vp 01' option.


when I try to run  this simple stap script  which print the vaule of
correct_wcount  ,


# t15.stp
probe kernel.function("do_mmap_pgoff@mm/mmap.c:901"){
        printf("the correct_wcount is : %d\n ",$correct_wcount)
}

here is  code snippets of  do_mmap_pgoff:


unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
 883                        unsigned long len, unsigned long prot,
 884                        unsigned long flags, unsigned long pgoff)
 885{
 886        struct mm_struct * mm = current->mm;
 887        struct vm_area_struct * vma, * prev;
 888        struct inode *inode;
 889        unsigned int vm_flags;
 890        int correct_wcount = 0;
 891        int error;
 892        struct rb_node ** rb_link, * rb_parent;
 893        int accountable = 1;
 894        unsigned long charged = 0, reqprot = prot;


.....





and here is the output of   'stap -l ' :
stap -l 'kernel.function("do_mmap_pgoff@mm/mmap.c")'
kernel.function("do_mmap_pgoff@mm/mmap.c:901")

Am I  missing something?

Any suggestion is appreciated.