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

[a qi <free4machine at gmail dot com>]

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.